Speed

Vintage 1954 GMC 350 Truck Ready for Cummins Power

47 posts in this topic

Hi all:
   I found this Forum while looking for a tire diameter chart of all things and thought you might be able to answer a couple of questions for me.
   I have a 1954 GMC 350 ser. (2 Ton) flatbed about 8,000 lbs empty;a friend is working a trade for a '91 12V Cummins and NV4500 which I want to install in my truck. I'm currently driving it,but the swapped-in 302 gas six is REALLY tired-it will just barely carry both Overdrives empty,and with even 1000 pounds on it,both boxes are in Direct or lower. (Clark 5 speed w/.84 overdrive,Brown-Lipe 3 speed aux. w/.74 overdrive,stock 2 speed rear with 6.40 top side.) I think this Cummins engine and the NV4500 will be a good set up. I'll be selling the Clark,but will keep the Brownie intact. So far,though,nobody has any ideas for fuel mileage. I'm getting about 8-10 mpg now,and that's if I drive with the Clark in 4th (Direct) and the Brownie in 3rd (Over). If it'll carry 18 mpg empty and go 65 I'll be good with that;I can live with 10-12 loaded (figure a car trailer with a car on it,average load) but more would be better.
   Anyone got some ideas? I read about the best rpm for mileage. According to my number cruncher I'd be doing about 2,000 r's at 60 mph-not as good as I'd hoped. 2500 rpm would give me about 74 mph;I could dial it down a bit to increase the mpg's. Thanks in advance for your input.
   Speed
   BTW-I live in Elko,and go to Reno fairly often.

Share this post


Link to post
Share on other sites

Welcome to the forums, Speed!  I'm enthused about your project.  My first job as a professional mechanic was responsibility for a fleet of 22 light and medium duty trucks, primarily 1949-60 GMC, Chevrolet, Ford and I-H.  One of my favorites was the 1949 GMC 350 with a 270 that I rebuilt.  I know your truck, current powertrain and chassis well, including the "Brownie" and industrial strength Clark 5-speed.  What an era, the Advance Design cab, too!  The 270 and 302 were the pinnacle of power and reliability for inline, four-main bearing sixes in trucks.  Until the mid-'fifties Chevrolet's dip-and-splash engines could not hold a candle, Ford was nowhere until the Y-block V-8 era; however, I-H had the quality BD and RD engines that made a mark.  That period was notable, over the years I have picked up a bookcase shelf of shop manuals covering the era.  Need facts?  I have them...

 

Your plan is reasonable, though there is a weight gain with the 12-valve Cummins.  Being an inline, it should fit the chassis.  The steering and front spring rate will have to be tested.  You could likely benefit from either linkage type power steering or a later retrofit integral power steering box.  Cooling will definitely need attention, the Cummins' BTUs may overwhelm the stock size radiator, though it's a big flow unit.

 

As for fuel efficiency, it's all about rpm with the Cummins.  If you can cruise at 1600-1900 rpm with your overdrive and tire diameter, I believe that 18 mpg is readily achievable.  My '05 Ram 24-valve HO was good for a consist 22-24 mpg with a stock curb weight of 7,800 pounds and driving within this sweet spot rpm.  For mileage, the closer to 1600-1700 the better with the HO engine.  Do the math on your tire diameter (revolutions per mile) and the gearing in overdrive.  You should easily be able to pull the overdrive when running empty—maybe even loaded on flat ground. 

 

Loaded fuel efficiency is a wild card.  Your weak point is the lack of aerodynamics compared to more modern trucks.  (The good looking Advance Design cab is worth it!)   I'd still expect 16 mpg or better with the 1,000 pound load.  What would kill the mileage is the anticipated 2000-2500 rpm engine speeds at cruise.  This engine will boost and flow fuel to achieve this speed, and mileage would likely be in the 16 mpg empty and 12-13 loaded.  I know from trailering and empty that each engine revolution over 1900 brings with it a noticeable drop in fuel mileage.

 

If you can re-gear or change tire diameter for 1900 rpm at 69-70 mph, the mileage gain would be dramatic...This fuel consumption thing is not about power, it's about engine speed.  The engine's torque rise is quick, and the torque peak (plus the next 300 rpm or so) is the point for efficiency and mileage gains.  Horsepower becomes a moot point with a diesel truck engine.  In my view, the peak horsepower rpm figure (approximately 2900 rpm with the Hypertech tuning) for the ISB Cummins engine is more like a redline indicator.  I can count on one hand the number of times my engine has been run to the horsepower peak rpm.  In 140K miles since new, it's seen its 3400 rpm redline twice due to passing situations that I should have avoided.  Frankly, the power is unimpressive beyond 3000 rpm.  I see 2400-2600 rpm as the ceiling—period.  In reality, I generally upshift to stay in the 1800-2400 rpm range to make usable power (torque plus horsepower) under load.  I'm always conscious of engine loads and fuel efficiency.

 

Note:  Here is a link to the tuning of my 24-valve Cummins with the Hypertech Max Energy software:  http://www.4wdmechanix.com/Hypertech-Max-Energy-Power-Programmers-for-Jeep-4.0L-and-Dodge-Cummins.html.  I'm not sure whether the tune improved or damaged mileage, there were many modifications to the truck at the same time...A friend has a stock HO Cummins truck like mine and has never seen beyond 18 mpg empty.  He insists on upshifting at 2400 rpm.  A new forum member in the Cummins fuel efficiency topic upshifts his six-speed manual transmission between 1100 and 1200 rpm when the truck is running empty, which I do as well with the automatic 48RE transmission.  This is the "just get rolling from a stop" routine that diesel truckers apply.  The NV4500 (rugged, I like it and have used it as a swap transmission) could easily be good for 1200-1300 rpm upshifts in your swap project.  Under load, perhaps a bit higher. Here's where we gain overall fuel mileage.

 

Incidentally, my current 4.56 gearing (plus 0.69 overdrive) with 34.6" diameter tires is for trailering and a hypothetical 55-65 mph cruise with a 7500-8500 pound trailer in tow.  69 mph is the outer limits for acceptable fuel efficiency.  (Of course, the Cummins 5.9L would be happy to make more speed and eat more fuel at the same time.)  I expect distinctly higher fuel costs for speeds beyond 69 mph.

 

Please keep us posted on this project.  Photos of the engine swap would be terrific!  I'm looking forward to continuing this conversation...

 

Moses

Share this post


Link to post
Share on other sites

  I understand about getting milerage-my current mileage in the GMC seems to run about twice the 5 MPG the old timers tell me I should be seeing,and my '81 Toyota 4X4 pick up,with its 300K engine,with compression so low I have to use Low Range to make it stay in my driveway,gets a consistent 20 MPG.

  I'm running Bias 8.25-20's on the '54 now,as soon as I can afford to I'll be upgrading to 9.00R-20's and that's the size I was using on the number cruncher I use. ( http://www.rocky-road.com/calculator.html) I don't think I can go any bigger than that on these wheels,and it's the 5 lug front,10 lug rear set up,so I don't know if bigger wheels are available in my bolt pattern. At a 42 inch diameter and with a .85 High in the 4500,and a .74 High in the 5531 Brownie and 6.40 axle,1800 rpm looks like 55.891 MPH. I tend to short-shift when I can-that 302 just sounds too busy for my taste at anything over 2200 rpm,even though they say it's redlined at 3400 w/governor. I know this engine and transmission have a LOT of hard miles on 'em.

   Am I right in figuring the 4500's High gear at .85? That seems to be "typical" for the overdrive ratio these days. I get a feeling I might have to find a single speed axle for this truck with a little longer legs than a 6.40. If I stick with a 2 speed with this lug pattern I'm solidly stuck with the 6.40 ratio. A 5.40 ratio would give me 66 MPH at 1800,if that ratio's even made. Okay,I just checked my GMC Assy.Manual,and they show  an "HO72" axle that's a 5.14 ratio,and THAT would give me 69.6 MPH at 1800 RPM! All I have to do is FIND ONE.

  BTW- I just picked up a pair of black leather bucket seats from a '90 Jeep Cherokee;a friend in Reno's giving me a pair of Astrovan pedestals,that SHOULD make 'em an easy install into the GMC. The stock seat's okay for short trips,but anything over 20 miles really puts the hurts on my back. The new seats will also make it possible for me to remove my cab gas tank and put some much needed storage where it lived. I've been running on a 40 gallon frame mounted tank,and know of a 30 gallon duplicate of it to install on the driver'side. (Just short enough to clear the Stack. ;) )

   I have some pictures of the truck as it is now,but don't plan to pull the truck apart for "Before/After" pics until I have the "new" engine/transmission in my possession.( A friend in Arizona is supposed to bring that engine and transmission,a PTO winch and a '48 Mack EG tractor to me,as soon as he gets his "ducks in a row",and take a 40 foot semi flatbed trailer and extra wheels and tires home with him.)

   Speed

Share this post


Link to post
Share on other sites

Speed...I get a kick out of the older engine power ratings.  Horsepower is always at some rod-stretching rpm for these long-stroke inline sixes with four main bearings.  (Flathead Ford V-8s and Jeep L- and F-head fours had only three mains!)  The only thing that saved these under-square engines was lack of compression.  Driving pre- and postwar trucks is where you learn to appreciate peak torque—not horsepower.  I had a '51 Ford F-3 with the last spur gear transmission and learned to shift up and down without depressing the clutch pedal.  The clutch was for stops and initial starts.  Double clutching was optional and the intended method of shifting.

 

Your 5.14 axle ratio idea would likely do very well.  You still have the two overdrives.  If you're bent on interstate speeds and the chassis is still taut enough, this is all workable.  (Check the spring anchor and hanger hardware carefully, the kingpins, draglink and tie-rod ends, too.  The steering gearbox is a rugged Saginaw recirculating ball-and-nut type and could still be functional, unlike a vintage Gemmer or Ross.)  The new seats make sense, the factory bench is always broken down and in need of major help.  When right, the OE seat is stiff as a board.  The auxiliary fuel tank is a solution, keep the tanks well out of harm's way, including consideration for side impact.

 

The PTO winch is a novelty.  Can you run it off the NV4500?  There's a plate and access to PTO gears, is there actually a PTO drive available for the NV4500?  If so, what is the use, wrecker winches?

 

That '48 Mack EG tractor sounds intriguing.  What's the plan?

 

Moses

Share this post


Link to post
Share on other sites

Old truck power ratings-135 hp i believe,for my 302;currently probably around 80.

   I found out the 5.14 is a REALLY rare ratio. Everyone who puts a bigger engine in his (or her) truck wants 'em. That's what I'll need though. I'll do some searching......

   I drove a '51 F-5 with that box as my DD for about 3 years,until I got my MG back together. I used to "half-double-clutch" the truck;that's when you'ready to shift,float it,pull it into neutral,then hit the clutch and blip the throttle to upshift,or pull it into neutral,jazz the throttle and hit the clutch and shift into the next gear down. Actually works pretty good. (blip and jazz-because it's easier to catch your gear on the way DOWN the rpm scale,going either direction)

   Regarding the driveability of the GMC,it's actually in pretty good shape;I went through it last Summer and checked the suspension,kingpins,brakes (I changed it  over to a dual reservoir M/C from a Chevy one ton van-same diameter bore,feels just like having power brakes.) :D Scrapped the HydraVac and original M/C,added an aftermarket adjustable proportioning valve inside the Right frame rail. (It still needs a little more front brake.) All the steering gear feels good,and it's due for another lube job sometime this Summer. Power Steering would be nice,but isn't essential. 

   This seat is original/"improved". The springs are all good,but it's so soft with padding it about folds me in half driving down the road.

   Those gas tanks are built beefy enough they'll easily total just about any of these "modern" cars that decides to tangle with 'em. The Right tank is under the bed on the frame rail,just behind the cab;the Left one will be in the same location with the rear ends at the same distance from the front of the bed,leaving just enough room for a 4" stack up front,with plenty of clearance. The tanks are identical in style and diameter,one is about a foot shorter.

   I'm not sure about the drive for the 4500 for a winch-I know they're available,but how much $$ ? After thinking on it,I'll run it off the main box so I don't have to spin both transmissions,and I can use the parking brake on the Brownie to keep it from rolling away while winching. I tell you what-those PTO parts are America's best kept secrets. Even the Dealers can't tell me what fits what unless I buy it NEW from them. (They must have a "Winch Wizard" in the back shop who works his magic to set up a winch for a particular truck.) I have 4 PTO drives in the shop,not a CLUE what any of 'em fits. Well,one is an air shift,so I assume it fits a 13 speed I had up for sale,and one is off an SM-465.

   I'd planned to build a crane with a base I could install in the stake pockets,and mount the winch under the bed with a pulley on the bottom of the headache rack to direct the cable either across the deck or up to the boom. Now,if this Mack comes in,and if it'll run,I've decided on an old school tow bed for IT. The PTO winch would work on that,either as a primary winch or a recovery winch. It has 1/2" cable on it,so I'm guessing it'd be rated at around 15,000 pounds or so on a single line pull. Actually,my first thought was to just flat bed it,but it already has the whole air system for pulling semi trailers,and that'd be useful on a tow truck too. B)

   Speed

   12-27-15

Update-I now have a 5th wheel RV trailer to make into a 32 foot Car hauler. (The plan includes adding an axle,since it only has two,with 5 on 4-1/4 hub pattern 15 inch wheels.) Once I get my '76 Chevy's heads replaced and get a pair of front tires for it,I think I'll go ahead and pull the flatbed off the big GMC and install the 5th wheel plate,and it'll be the 2 car hauler. (Maybe 3 if I can ramp one up on the tongue.) Come warmer weather I'll drag the trailer to town and get it stripped down to a frame (Hope the price of scrap is up again,that'll help me with parts/supplies to get this done.) and suspension,get the third axle in,get the brakes re-wired and get the lighting done. With the third axle at the rear,I could add a 5 foot dovetail,making it about 36 feet of space,and some room on the tongue for either crates,parts or one end of a car or trailer if I make a ramp for it.

JS

Edited by Speed
Correction/addition of information.

Share this post


Link to post
Share on other sites

Speed...The spur gear could be shifted without gear clash, using a variety of creative techniques.  The key was engine speed synchronized to gear speed, with straight-cut gears and no synchros the challenge.  These transmissions were rugged and held up well if you shifted them properly.  Fully double clutching or sliding to neutral and matching engine to gear speed with the throttle were not alien concepts in the pre- and postwar era, though this four-speed gave way to a compound low and synchromesh (2nd,3rd and 4th gears) T-98 in 1952.  Spur gears simply could not compete with GM's SM420.  Ford did not have synchromesh in any transmission before 1939.  During high school years, I had a '38 Ford half-ton with straight-cut gears and no synchromesh.  No hydraulic brakes, either.

 

The GMC steering gear ratio is slow, these gears are very smooth thanks to the patented Saginaw recirculating ball-and-nut design pioneered by GM.  I have rebuilt many Gemmer and Ross boxes, few GM with ball and nut.  GM with worm and sector are another story, be very pleased that your truck does not have a worm and sector, worm and roller or cam and lever steering gear!
 
Tanks sound well in hand...You'll like the capacity.  110 gallons will easily get me from east of Reno/Sparks, NV to Moab, UT and back with a good margin of fuel to spare when running empty.  (Estimating approximately 8900 pounds curb weight with full tank of fuel, I need to weigh the truck and confirm.)  This allows for selective (I.e., less costly per gallon) fuel stops when trailering, too.  I-80 at Wells, NV or Elko, Salt Lake Area, Green River even Moab are better fuel stops than in between.  On Highway 50 heading home, I avoid fuel anywhere but Ely and Fallon. 
 
Curious what you wind up doing about the winch PTO.  The Brownie will certainly work if you have or can find a drive...
 
I like your Mack ideas, creative and practical if the older technology powertrain and chassis will meet your needs.  The boom and deck could make a commercial tow truck or a museum/parade piece.  You would have plenty of power if not in a hurry.  This is unique, vintage technology with a stunning profile!  Wow...go for it!
 
Moses

Share this post


Link to post
Share on other sites

That's one thing I love about the OLD Mack Trucks-they're usually nowhere close to fast,but they'll pull the top off a Mountain if you can find the traction and something to hook the chain to. I haven't checked the Mack for a PTO drive,it's about 600 miles away,but it probably has one. It has an OHV 354 C.I. six (Made by REO) and that 5 speed with a vacuum(?) shifted integral aux. box-Mono-Shift,I think.(Sitting here thinking of a way to shift it electrically without causing gear damage,so I can run it like a 2 speed axle. An old school Mack driver I know said he'd seen 'em shifted via cable,vacuum and even hydraulic,but never electric. Apparently,since it has to be "floated" into gear,the shift either has to be carefully timed or the mechanism needs to be able to shift kinda gently. I have an idea,but I'll need the transmission before I can check it out.) I can only guess at gearing (The Mono-Shift is a Direct High Gear,with an Underdrive),so I'll be surprised if it'll go more than 35-40 down the highway. It has 10.00-20's on it. It HAD a 5th wheel,but the guy who has the truck sold the plate;I still have the one off my '45 EH,so that's an easy fix if I want to use it.

   My biggest concern on the Mack is brakes-in the 14 years I owned the '45 EH,it had actual brakes for about 50 miles,on the way from Reno back to Elko,towing my '62 Chevy one ton duallie,and that was after spending $200.00 for a new Master cylinder. The rest was just planning my moves carefully,driving slower and using the parking brake when needed. (I only used it on dirt roads,and streets as needed to get to the job locally,to move trailers and mobile homes,push cars,drag rakes etc. Rarely over 5 mph)

   I figure the tanks I have in mind for the GMC should give me at least 900-1,000 miles range,worst case. At today's price,I'd be looking at around $230.00 to fill it from empty.

   I've always liked the SM420-especially the LOW first and reverse. When my Brother and I built my '74 Chevy one Ton,I had the option to choose which transmission I wanted;we had my SM420,an SM435 and an SM465. I chose the 435,but regretted the choice later. I SHOULD have kept the 420 even though the 3rd gear synchro was shot.

   I actually like the steering in the '54;it appears to need the toe-in set,the front tires appear to be scuffing a little,but it's not bad. I have a hydraulic ram for a power steering set up from a '73 Chevy C-60,but the pump had a broken shaft. (I bought the steering box to replace the manual steering box on a 66 Chevy C-60,and the seller said I could have everything related to the steering,so I went for it. The truck drove so nice with that box I never bothered with the power steering. (It was a bolt-on swap but I had to re-clock the steering arm about half a dozen teeth on the splines to get it centered.)

   As for the tow truck idea,it'd be handy for me because I seem to be given a lot of vehicles missing wheels,suspension parts and axles. I could just skid 'em onto my car trailer,but they rip up the deck on it,and they don't slide off easily at all when I reach the landing spot. If I build a removable actual hoist,I could ise it for loading a truck,swapping out engines,dismantling old Mobile homes,etc. My favorite idea is still to build an Old Style tow truck with the Mack-I can see it in my mind,and it's gonna be so cool!

   Oh-I wanted to ask,what do you think of that New Venture six speed? Is it as strong as the 5 speed? Does the 6th gear have a taller ratio than 5th in the 5 speed? Worth searching for?

   Speed

Share this post


Link to post
Share on other sites

That electric shift might follow the approach with modern transfer cases.  Look into the electrical engagement mechanisms on these late units like my Dodge Ram's NV273D.  Worth a look, may provide some ideas...

 

The NV5600 is a sturdy unit overall, though there have been synchronizer problems, the parts availability for the unit is not good, either.  You'll find ratios at this link for the Dodge Ram version.  Author does mention synchro troubles under load.  We have a friend whose Ram/Cummins and trailering wore out (overwhelmed?) the synchros in his NV5600.  It's a busier unit for rebuilding, too, though I would like the challenge!  Note the torque specs, the HD upgrade was apparently not in the cards for Dodge/Ram:  http://www.dieselhub.com/trans/NV5600.html

 

Moses

Share this post


Link to post
Share on other sites

 I'll see if the Dodge dealer here will let me look at their info on adjusting the T/C shifters on the late models. (There will be pictures...) That's gonna be a later on kinda project,good idea though. I'll ALSO see if there's any retro-upgrades for the 5600. It appears to be substantially beefier than the 4500,judging from the difference in weight,torque rating and I like the gearing better. (It's almost MADE to be linked to a Brownie.) It sounds like the synchronizers are also functioning as thrust washers,from the reference to troubles "under load". Do you know if there's a place to install a debris filter on these transmissions?(assuming they have some sort of oil pump to lubricate the input and output bearings)  I'm not too worried about the synchronizers as long as I don't have to worry about chunks circulating through the gears and bearings,but apparently,breaking a synchro ring creates a bunch of end play,eventually leading to a "put on your walking shoes" catastrophic failure. If you're set up for it,maybe there's a market to do rebuilt and upgraded 5600's. I don't know if I'd be able to afford a 6 speed of any condition,but right now I figure that's a better possibility than I have of finding that 5.14 axle. I'm thinking the delivery trucks (UPS Van styles) of the 50's/60's would be most likely,as owners of those were more concerned with the cost of operation,so  they'd more willingly order the taller gearing. I may have to advertise for that axle or gear set. BTW-How are you at setting up a ring-n-pinion? I haven't had much success with it.

   Speed

Share this post


Link to post
Share on other sites

Speed...Looked at the parts schematic, no pump, filter or any other creative lubrication methods, just a typical manual transmission that relies on slinging oil upward from the spinning counter gear, the time honored approach.  Would be very busy inside the case and likely not a candidate for an internal filtration system.  However, here's an idea:  Advance Adapters has used an external oil balance tube on the Atlas transfer case.  They ran a transparent oil resistant plastic tube from the drain plug hole to the fill plug hole to keep oil somewhat level and allow filling to a specific point.  Perhaps that triggers some thoughts. 

 

You might devise an external pump (electric) and filtration system that uses these two plug points for access and return.  Weight of the oil would be a factor for circulating oil efficiently.  There would be a need to assure the proper level of oil in the transmission at all times.  No cavitation would be essential.  There are hydraulic pumps and filtration systems that can accomplish this.  Overfilling must be avoided, too much lube would blow the front bearing retainer and other seals out of the transmission.  Available oil would be a specific amount that assures safe oil level in the transmission at all times.  The pump could be operated periodically if more practical, like when the oil is warm/hot to aid circulation.  A spin-on filter compatible with the oil viscosity would work well here.  Here's a quick view of some filtration options from the Summit Racing catalog, you would need an inline pump:

 

http://www.summitracing.com/search/brand/derale-cooling-products/on-sale/yes?N=4294906750%2B4294924186

 

Rebuilding the NV5600 would not be a problem, parts sourcing would.  Likely, if enough volume existed, a machine shop (U.S. preferably) could produce improved synchros.  Most suppliers go to Taiwan for this kind of manufacturing, the metallurgy is better than China proper.  It could be done.

 

I've always been academic with mechanics.  As a light and medium duty truck fleet mechanic in the late 'sixties and early 'seventies, I worked on everything and anything that came up.  I have accumulated four bookcases with shop manuals and service related information.  I don't hesitate to work on anything that has a companion shop manual.  Axles are among the work I do, automatic and manual transmissions and steering gears, too.  We ran a restoration shop for vintage and muscle era engines, transmissions, axles and steering gears for several years.  My library coverage dates back to 1925 with automotive and trucks, Harley-Davidson from 1917-98.  Ring-and-pinion work is not as daunting when you follow a factory workshop manual or traditional professional series guidebook.  I always do.

 

You might find a late Cummins ISB version of the NV5600, though it won't be cheap if in good condition.  You're a real truck driver and could keep the synchros alive by driving sensibly.  I like your 5.14 idea, it's less costly.  Bread trucks and delivery trucks?  Don't give up on that idea.

 

Moses

Share this post


Link to post
Share on other sites

What do these transmissions use for lube-90 wt. or ATF? On the T/C in my Bronco II it calls for ATF,but I changed it over to a 10Wt. synthetic motor oil. It's been working like a champ for 4 years now,and that includes highway trips,Four Wheeling and two scrap runs of about 15 miles one way towing a car trailer with over 9,000 pounds of metal (Hell of a load for a 2.8 Liter to have to pull!),and it even gained me a couple of miles per gallon in the deal.

   I may have to put the 5600 and the 5.14 axle idea on a back burner while I get other stuff done,and while I wait for "the deal I can't pass up".  Looking at the details in my Assembly Manual,I was mistaken on the 5.14 ratio-it's for a ONE ton. The BEST factory option for the 2 Ton axle is an H-150,with a 6.17 gearset,better but not nearly better enough. The actual rear axle I have is an Eaton 1350,but I don't know if a single speed carrier will fit the housing,since I have the 2 speed. If it WILL,I still have to find a single speed 2 Ton rear end,THEN try to find the gear set I need. I'm pretty sure they used the 5 lug/10 lug wheels well into the 70's,so maybe I can find a complete rear that could be installed on my springs. I ran across an abandoned truck,about a '70 or '71 Chevy C-60 last Summer that had the same set up,wheel-wise,as mine and a single speed punkin,but it was gone when I went back to get it about a week later. I think that's what I'll have to do.

   I'd intended to hire a friend of a friend to do my conversion,since he does a couple per week,and knows all about the conversions,but everything I'm reading tells me that except for a little fabrication work it's a pretty easy swap,so I'll probably do as much of it myself as I can,and call in the experts if I get in a bind,or for special stuff,like the drive lines. (I'll need to damn near start over on those-my rear one,from the axle to the output of the Brownie needs to be re-tubed 3 inches longer to get rid of a vibration in the slip yoke,and the one from the Brownie to the transmission will need to be shortened and a new front yoke to fit the 4500.) Not sure about cost-just these changes will be around $250.00. I'm going to find out about changing all four yokes and switching to a more common u-joint type,which essentially would be starting from scratch. (Made that much easier if I find a later rear axle to install.) I think that'd smooth the drive train up a bunch,too.

   Something else I was thinking about is an intercooler. Would that be worth doing? What external measurements would I be looking at? Would there be a problem with mounting it under/behind the front bumper,angled back at the bottom (---O----------O/ <  only more so) for ground clearance,with ducting and a couple of electric fans to keep air flowing on low speed hard pulls. I was also thinking about building an air dam under the bumper from thick conveyor belt about a foot wide,to maybe help the truck bash through the air.

Speed

Share this post


Link to post
Share on other sites

Speed...Valvoline has the best oil application chart online.  I downloaded a PDF that's at these forums in a reply.  I use these recommendations, Redline is another source if you can afford the price of admission...

 

Sounds like you hit the wall with the axle ratios unless you swap out the entire rear axle for a later model application that might fit.  Two-speed could reduce the available applications.  The NV5600 or an NV4500 are at least a Dodge Ram offering for mate-up to the Cummins.  Drivelines are always a part of these swaps.

 

Intercoolers provide definite gains, though any kind of boost in diesel power has its downside.  I'd try stock first and see whether that's the power you want.  The intercooling makes a denser charge, advantageous but also a boost in heat.  A pyrometer is in my towing future, should be yours too if you have access to one.

 

As for aerodynamics, the Advance Design is not a real candidate.  They look fantastic, though!  An air dam might have minimal benefit.

 

Moses

Share this post


Link to post
Share on other sites

Yeah-my old truck is about as aerodynamic as a barn door.

   Regarding axle ratio,I'm pretty sure I can fit a later,same sized single speed under the truck;the critican concern,for me,is spring width at the spring pads. It's hard for me to imagine the spring spacing changing enough to be a problem. Within limits,I can make some offset centering plates to line up the  center bolts,and just set the U bolts a little farther apart to compensate for the change. Brake lines are no problem,wheel lug pattern is "easy"-they only had a couple or three different hub styles avaailable for the 1-1/2 and 2 tonners. A late 60's or early 70's truck would very likely have gearing suitable to run at 60-65 mph with a Direct 4th or 5th gear,especially with an engine bigger than a six or a smaller smallblock. I expect the brakes would be better,seals and bearings would be easily available,and a suitable yoke to upgrade to a better u-joint would be easier for the driveline shop to find. AND a later truck MIGHT have brackets I can use to put some SHOCKS on my truck! I'll have to look and see what kinda year-spread I can use,get some measurements,etc.

   I guess I was figuring the intercooler might give a little "free" horsepower,so I could get away with less throttle. You're right though,better to leave things as stock as possible-less to give problems later on.

   On my list of "to do's" is re-gauging my truck;I'm getting a couple of extra dash panels,and re-fitting them with more modern gauges,including a Tach and a Pyrometer,and the gauges are whether I change to Diesel or not. I'm so tired of not being able to see the meters at night-it'd be wonderful to have internally lit gauges,maybe with LED's. The ones I have work okay,but the lighting on that model truly sucks,and once they start getting all faded and discolored they're even hard to see in daylight.

Speed

Share this post


Link to post
Share on other sites

The later axle does make sense in a variety of ways...Lamps are vintage and were dim when new.  Classy looking but not practical.  You might look at the classic/street truck aftermarket offerings, Advance Design trucks are popular, and there are LED lamp replacement dash inserts that might keep the original shapes and cues but actually offer luminance.

 

Shocks would be nice.  The springs rates were so high and speed limits so low that shocks were non-essential.  This is a very interesting and fun project...

 

Moses

Share this post


Link to post
Share on other sites

I think this truck will be as fun to build as it'll be to drive,and I LOVE to drive it already. The only factor that keeps it parked is the cost of operation. Hey-I just ran across this set up;I had considered something like it for the 302. What do you think? They say they even work on Diesels. http://globalenergydevices.com/dry-duo I'm curious what kind of "power increase" they're talking about. As is typical in my life,the fun is only limited by what I can afford to spend on it. Much of what I do seems to be "Redneck" natured because of the expense. Part of the fun,though is finding a way to make things work when you can't come up with the "right stuff". (It's interesting to see how some people think if you can't buy a part to make something work,it just can't be done. That just makes me think,"What could I modify to make it do that?" That's actually like my Signature on another Forum;"HMmm-What could I make outta that?"

   I think I can make LED's work on about 99% of the truck and have it still look "original". I ALWAYS convert to sealed beam Halogen headlights. My GMC's amber fog lights are also Halogen sealed beams. I tried LED 1157's (two different designs) for the tail lights,but just couldn't get them bright enough to make me happy,so I'll probably go with the rubber grommet mounted LED's like the OTR rigs use,as well as the side markers,and Harbor Freight sells a rubber cased Halogen work light with a swivel mount that works awesome as a back up light.(TWO of 'em) (I'll be "light poor" before I'm done-I have the GMC,a car trailer,my '66 Pontiac Catalina,probably the '48 Mack EG and eventually a '53 Chevy 1-1/2 Ton dump truck I'll have to do. (The dump truck will get the GMC's 302,rebuilt,and possibly the Clark 5 speed when I switch to the Cummins.)

   If I can work up the brackets for tube shocks on the rear (I'm thinking something like quad Rancho 5000's),I have an OEM set of lever action front shocks off a '49 Mack School Bus I think I can make work. (Or,more of the afore-mentioned Quad Ranch 5000's).

   Naturally,there are a LOT of things that just take cubic MONEY-no substitutions possible. Shocks,the change to Radials,the lighting upgrades,etc. ,but I'm always running across cars,trucks,other stuff people give to me to get it out of their way (or USUALLY to get it out of their WIVES' way) that I can sell or trade for stuff I need. And MOST of it doesn't have to be done right away,so I can piece it together,or save up for it,or not do it at all and just dream of getting it done eventually. I really enjoy creating a plan for what parts I'll use,how I'll make things work,even what they'll cost. I'm a "Listoholic";I make lists of everything,what I need to get done on a particular day for instance. If it isn't on the list,I'll probably forget all about it.

   Once I get started on the Cummins Conversion,you're always welcome to come up and get your hands dirty and enjoy a cup of coffee. Well,you can come up anytime for coffee.

   Speed

Share this post


Link to post
Share on other sites

Speed...I tried a homebrewed recipe for a hydrogen gas supplement on the 4.0L Cherokee several years ago.  It used baking soda and an electric element in a glass jar, very primitive and, frankly, it proved useless.  This "kit" seems more sophisticated and may actually work.  The concept appeals to me, though we all know where "concepts" often lead.  I'd like to read testimonials and documented tests.

 

Motorheads have a penchant for "projects" and planned doings.  I have my share, too.  The coffee break sounds tangible and appealing!

 

Moses

Share this post


Link to post
Share on other sites

The Mack is a time piece!  Reminds me of the RD406 powered I-H dump truck I maintained as a truck fleet mechanic in the late 'sixties.  The torque is unbelievable, the gear sets as well.

 

Fun to watch the videos.  Sounds good!

 

Moses

Share this post


Link to post
Share on other sites

This Mack's engine ran great considering it had an updraft carb I couldn't even remove. (My hands just don't articulate that way.) It has a 5 speed with a Direct 5th,and 6031 Brownie and single speed axle with 6.86 gears. I was especially proud of the fact that,with absolute garbage for wiring when I bought it,(I touched the headlight wiring and all the insulation crumbled and fell off.)we finished up with EVERYTHING working (even the little marker lights on the headlights!) and a 140 amp Leese Neville one-wire alternator. (The wipers never worked,but THEY weren't electric-they were vacuum.) We used a wiring harness from a '75 Chevy pick up,as well as the fusebox, switches and relays from it. I was able to use the stock "Mack" knobs for the switches and the cigar lighter. I ended up selling the Mack to a local Propane Distributor who had one like it as their very first truck when they opened in 1954. I should ride to Wells sometime this Summer and see how (or IF) the restoration of the Mack is going.

Speed

Share this post


Link to post
Share on other sites

The Mack lends itself to restoration.  The new owner should be motivated, this is an intact truck...with interesting gear works, too!

 

Thought I recognized the fuse box.  We had '70s and '80s GM trucks.  Our '73 K10 4x4 was a winner with 350 V-8, SM465, NP205 and 12-bolt Saginaw rear axle.  A favorite!  The two Suburbans were each 3/4-ton 4WDs, an '86 and an '87 both 350s, '86 carbureted, the '87 had TBI, THM400s and Corporate 14-bolt rear axles.  GM built great trucks in that era, a real rival was I-H through '75.  Ford's F250 High Boy 4x4 got the job done, too.  An F350 4x4 by 1979 was even better.

 

Moses

Share this post


Link to post
Share on other sites

   Hi Moses;

I have a minor update regarding my gearing;I found more accurate information that says this.

   My Clark is a 264VO,with a First of 6.06,Second is 3.50,Third is1.80,Fourth is 1.00,and Fifth is a .80 Overdrive,not a .85 as I'd guessed.

   The Brownie is a 5531,with a 2:1 under,1:1 Direct and a 0.72 over,not the 0.74 I was told previously. 

   At 2000 RPM,in low,low and low,I'm going 2.25 MPH. In REVERSE,I'm going 2.275 MPH.

   At my 302's REDLINE of 3400 RPM,in low/low/low it's 3.82 MPH,in REVERSE,it's 3.87 MPH. :lol: How cool is THAT? Do I have enough gearing :wacko: ?

   Speed

Share this post


Link to post
Share on other sites

All about gearing, Speed!  A vintage CJ from the Kaiser Era with a T-98A transmission could climb a tree in low range, compound low gear of the transmission.  The 12V starter motor could crank and start the engine on a steep gradient in gear with the clutch engaged.  I'm sure the 6V starter in your GMC could do this too with the gearing you describe, at least on level ground!

 

That's how these vintage engines survived.  A realistic highway speed for that truck was likely 45-50 mph with any kind of load...on flat ground.

 

Moses

Share this post


Link to post
Share on other sites

Yeah,I think it'd run 50 with both boxes in Direct,even loaded and with the 90 meager horsepower it probably has now.

   I've driven this truck half a block on the starter to get it out of the traffic when I ran it out of gas. I've also used the starter to nudge it just a little when using the clutch might be too much.  

   Hey-I'm planning to get my rear driveline section replaced as soon as I can swing it;It's built an inch or so too short,and is getting a wobble at the slip yoke from not having enough spline engagement. I want to upgrade it to more common u-joints and replace the slip yoke with a new,and longer splined one,and go with a little beefier tube. I figure,with TWO overdrives and the 6.40 axle I'll be running for the next little while,that driveline will be spinning pretty fast,so I want it to have every advantage I can give it. The driveline shop here said they'd re-tube it an inch longer and install near new u-joints for $250.00,but if I can afford it,I'd rather start fresh and go with a little overkill. What components would you use? Fine spline or coarse? What size u-joints? I know they'll have to have grease fittings. What's common,but suitable for what I'll be doing? I'm told they do an excellent balance,and that's gonna have to be MANDATORY with me,regardless of what else they do. I'm not going to try to make the whole drivetrain perfect (I'm sure both boxes have loose bearings,etc. that won't be helpful,and ALL the u-joints could probably stand replacing-LOTS of expense there. THEY might get upgraded next.),but I'll work from the back forward,since that's the problem I KNOW needs to be fixed;a small problem at the nose will often magnify as it goes back,to become a BIG problem at the tail.

   I decided to change out the taillights on the GMC;I have a pair of taillights from a '66 Pontiac I'm mounting just below the deck on each side. I can use the ones I have on the truck now,from a '70 Chevy stepside pick up,on the utility trailer I'm building from a '32 Ford rear axle and a '40 Ford pick up bed,solid mounted,no springs,hitch welded to the end of the torque tube. the fenders were toast so I'll use a couple of little "cycle fenders" off an old wooden trailer that self destructed hauling a Harley in from Ryndon.

   Speed

Share this post


Link to post
Share on other sites

Hi, Speed!  First off, before spending money on these drivelines, are you committed to the current gear train and engine location?  If you do a Cummins swap with an NV4500 or any other creative magic, you'll need to resize the driveshafts.  When you're considering the current upgrades, the length of these shafts needs to be "permanent".

 

Guessing that you're restoring the GMC and keeping the gearboxes and engine position, the best build of a driveshaft is heavy-duty joints and couplers.  The more splines, theoretically, the stronger.  All of this is relative to the engine and torque applied.  90-110 horsepower would be easy on just about any spline arrangement.  For the Cummins, increased spline count would be desirable.

 

U-joints should be quality, I like Spicer, Detroit or Delco for OEM replacement, NEAPCO and others produce decent products, too.  You do want "heavy-duty", often the HD is a permanently sealed joint without a drilling for the grease fittings.  Front live axles required sealed joints at the steering knuckle joint of the axle shafts for that reason.  If you want grease fittings like the OE, make sure the joint is rated well for your GMC application...

 

Very important to driveshaft life is the driveline and U-joint angles.  Your truck is relatively stock and certainly does not have a "lift kit".  I would still check the driveline/U-joints angles.

 

Moses

Share this post


Link to post
Share on other sites

Hi Moses;

   I'm planning to stick with the Brownie,and the axle I use will have to be the Eaton 1350 2 speed until I can find a later single speed that can use the same lug pattern,at which time I might have to re-do the driveline AGAIN. For now,since that last link already needs work,I figure I'd rather do it up right than patch it up. That way,no matter WHAT,I can drive it and not worry about it. I'll do all my adjusting in the section between the Brownie and the 4500. So far,I've been hearing the bellhousing to block line can stay the same with the Cummins as with the engine I have. Therefore,unless I've been misled,the only actual change would be the shaft between the Brownie and the 4500. I don't have measurements to compare yet,as I'd intended to get everything else put together then measure and order the driveshaft. For u-joints,I like Spicer too,but the guy at the driveline shop says he's having trouble with price on 'em,so I think he's switched to NEAPCO. I'd prefer the grease fitting to the added strength of the HD option,since I don't anticipate doing anything that could break one. (Theoretically,an axle would twist off before I could break a u-joint.) As it sits now,the drive line angle is suspect between the end of the transmission and the axle yoke,the "adjustment" being the height of the Brownie. When Jess looked at the truck to find the vibration,he said it looked good as is,but without his angle tester he wasn't solid on that. If it turns out to need adjustment,I can raise or lower,or tip,the Brownie a little.

   I just measured my tires and they're 38.5 inch diameter,so "Theoretically" my low,low,low speeds should be even lower,but they figure faster (or LESS slow). At 3400,it went from 3.82 to 3.96 MPH-How did THAT happen??

   Speed

Share this post


Link to post
Share on other sites

All of your OEM U-joints were grease fitting type, I know from a good deal of personal experience!  I serviced these period trucks from high school in the mid-'sixties onward, and as an equipment operator, "lubrication engineer" was part of the job!

 

Understood that you'll be reworking just the driveline with known, permanent length.  The Brownie does sound like the practical U-joint angle adjustment point...I'd adjust U-joint angles before taking driveline length measurements.

 

What's the final low, low combined transmission, Brownie, two-speed axle reduction ratio?  We can do the math on tire revolutions per mile and resulting MPH based on the gearing.  Let's see where the error is...

 

Still excited about the Cummins engine swap...What's the weight difference between the Cummins engine/flywheel/clutch and your GMC engine/flywheel and clutch?

 

Moses

Share this post


Link to post
Share on other sites

I'm only guessing on the weight difference,but I'm going with something in the 300 pound range. The 302 is a pretty heavy engine,and the Clark isn't very light either. Even if I'm off a bit I don't think it'll be enough to be a problem. Jess is pretty good at his job,so I'm going to figure my DL angles are okay.

   Now-for gearing,I went with:

38.5 inch tire diameter

6.06:1 Low Clark 264VO

2:1 Brownie 5531 Low

8.10:1Eaton 1350 Low

3,400 RPM

================

3.968 MPH

   I see where I screw'dup-it was in my first total. I suspect I was guessing at the low range ratio in the axle,before I found a definite number. I think I was guessing it to be an 8.41 or something like that. THAT number figures out to the 3.82 MPH figure. Okay-I got it now. Here's the number cruncher I use. There's more stuff you can do with it.

   http://www.rocky-road.com/calculator.html

      Speed

Share this post


Link to post
Share on other sites

The calculators online are very helpful, I use them all the time.  Have an old Wolverine camshaft selection software that offered even more info, unfortunately it's 3.5" disc and old DOS.  Windows 7 eliminated backward compatibility to earlier DOS software.  That terrific Wolverine program and its "utilities" functions became a relic...Glad there are online calculators! 

 

You "did the math", Speed, the numbers sound good!  Plenty of gear reduction...

 

Moses

Share this post


Link to post
Share on other sites

I woke from a dead sleep last night to realize a '66 Chevy 60 Series I "restored" 4 years ago has the exact axle I need. Don't know what gears it had but it was a Limited Slip,and with a 292 and 4 speed,it ran about 60-65 comfortably on the 50 mile delivery to its buyer's ranch. (I wonder if that truck's in the "back 40" yet....)

   Speed

Share this post


Link to post
Share on other sites

Good choice, Speed...Take measurements, it might be close...

 

There's an Advance Design long bed pickup in the neighborhood with a very straight and rust-free (Nevada?) sheet metal.  Has the quarter window cab, very sharp profile.  I stride past this truck on my early morning walk.  I've considered the truck with a Cummins diesel or Duramax, and even a 292.  The 292 is a pristine swap with a '55-'59 V-8 iron bellhousing, easily fab'd front mount and a direct bolt-up for the SM420.  The longer chassis is an open driveline (no torque tube), which makes this even easier. 

 

With just minutes to think about the truck, I have considered the practicality of tugging a travel trailer behind a vintage truck at interstate speeds.  The biggest weakness would be the narrow, high-stack springs...Some would simply find a later 4x4 chassis (a K20/2500 would be likely) with beam axles.  They'd swap over the body to the modern chassis.

 

Have you towed bigger trailers with any of this vintage light truck chassis stuff?

 

Moses

Share this post


Link to post
Share on other sites

   The truck you're describing,if I'm not mistaken,is likely a one ton. They (the ones with a 9 foot bed) are quite collectible,so if you can snag it for a fair price,you should. If it was mine,I'd go with a 292,alternator,install electric wipers from Newport Engineering,swap in a 4.10 pumpkin from a late 60's 3/4 ton GM truck,swap the Master Cylinder over to a dual reservoir;if you find the right one at a parts store for a drum/drum system,it's just a matter of a mounting bracket and a couple of brake lines. If you use one set up for a disc brake front end,just pick up an adjustable proportioning valve from Summit,put it in the line to the front brakes and you can adjust the pressure to work as you like it. (I did this on my '54 two ton.) For SOME reason,getting the new M/C with the same bore diameter the truck has makes it feel like power brakes,but not as sudden. If the brakes aren't beefy enough,you can get the kit with a booster,but I don't think you'd need it. 

   Personally,I'd run it with the springs it has and see how it drives. (Maybe remover a couple of leaves if your trailer's not a 5th wheel or goose neck.) If you want different springs,it may be possible to find later,wider springs in a wrecking yard,and if you grab the shackles and frame brackets,it might not be too tough to just change the whole set up to the older truck.  The problem I see with going to later axles,frame conversions,etc. is that the wheels will stick out too far. If you go with a cab & chassis,you might cover it by going to a 2 ton front group (longer hood,wider fenders,still fits the smaller truck cab),but it'd be a bit of work to make it all gell. If you do it,PLEASE don't change it over to hanging pedals-that just ruins the character of the truck.

   After I ruined the second rear end on my '57,I used a rear end from a '74 Chevy 4X4,with my stock springs,the newer u-bolts and spring plates,and I made some shock mounts to use my old shocks. The '57 driveline bolted right up. It was MUCH easier than I was told it'd be. (wrong spring spacing,wrong spring width,wrong this,wrong that,etc. There USED to be an outfit that sold a roller bearing kingpin kit that was GREAT,but they're not around now.   

   Also,(and I'm not sure one is offered for a 3/4 ton) a tapered roller wheel bearing conversion seems to make these ol' trucks drive better on the highway. You MIGHT be able to work up a conversion if you're in good with someone at a bearing house.

   If you score that truck,get logged on with "Stovebolt Forums".

     http://www.stovebolt.com/ubbthreads/ubbthreads.php

(If it's a GMC,it's "oldGMCtrucks.com" .) Better yet,log in on both-Lots of good information and good people there.

    They have a lot of information on conversions to disc brakes,etc. In the Gallery are some pics of some trucks I've owned.

    I towed a 35 foot 5th wheel RV a lot with my '57 GMC pick up. Even being a half ton it did fine. (I shut down a Ford one ton with a similar sized trailer between Immigrant Summit and Battle Mountain,he backed out of it at about 80,I ran it up to about 90 before I let up.) ONE thing you'll want to do is get a pair of 16.5 wheels and 9.50-16.5 tires for towing. I noticed they make the truck rock-steady with a big trailer.  Also,make damn sure your trailer brakes are working right. I'm not sure my trailer brakes EVER worked,and the pick up's brakes worked fine unloaded,but doing all the braking for a trailer that size gave them a working life of about 100 miles.  When I brought the trailer from Elko to Reno I wasn't too worried when the brakes went bad,because I knew the road very well,but on the move from Reno to Boise,it was a different story. I discovered the brakes no longer did as I was pulling off 80 into Winnemucca. I didn't have the time or the money to go through the brakes so I just bashed on,regardless,with my ex,Dawn,leading the way in her '79 Mercury Zephyr,using her CB to tell me what was coming up-idiot drivers,steep grades,cattle,etc. I didn't know the trailer was as heavy as it was. On THAT trip I had to skip the 16.5's,as they were showing wire and I couldn't find used tires that size. I ran E rated 215-85R-16's on all four corners,and between Caldwell and Elko TWO of 'em started to blister;once I got to Elko another one threw tread. APPARENTLY,this size,even E rated,was too small for the load. After that,I started running 235/85R-16 E's,and never had another tire problem. I DID have to replace the 347 V-5 (3 dead cylinders) with a '68 Pontiac 400,and grenaded two rear ends,one towing the RV out to storage (Exploded the spider gear case,bent the pinion shaft,cracked the punkin.)and one just pulling away from a traffic light on my way home from work.(broke the ring gear in 5 pieces,none stayed secured. It was so weird-pulled away from the light,shifted to third at about 2500 rpm,let the clutch out and it just coasted to a stop,still idling in gear. Got out and looked under the truck,driveline still spinning smoothly..... :huh: 

   Speed

Share this post


Link to post
Share on other sites

   The truck you're describing,if I'm not mistaken,is likely a one ton. They (the ones with a 9 foot bed) are quite collectible,so if you can snag it for a fair price,you should. If it was mine,I'd go with a 292,alternator,install electric wipers from Newport Engineering,swap in a 4.10 pumpkin from a late 60's 3/4 ton GM truck,swap the Master Cylinder over to a dual reservoir;if you find the right one at a parts store for a drum/drum system,it's just a matter of a mounting bracket and a couple of brake lines. If you use one set up for a disc brake front end,just pick up an adjustable proportioning valve from Summit,put it in the line to the front brakes and you can adjust the pressure to work as you like it. (I did this on my '54 two ton.) For SOME reason,getting the new M/C with the same bore diameter the truck has makes it feel like power brakes,but not as sudden. If the brakes aren't beefy enough,you can get the kit with a booster,but I don't think you'd need it. 

 

You build a good case for this truck, I may take a closer look... I've done brake (dual-braking system) upgrades on a number of 4x4 projects, a smart safety option.  Made a nice setup for the '55 CJ-5 through-the-floor pedal arrangement featured in my Jeep CJ Rebuilder's Manual: 1946-71. 

 

   Personally,I'd run it with the springs it has and see how it drives. (Maybe remover a couple of leaves if your trailer's not a 5th wheel or goose neck.) If you want different springs,it may be possible to find later,wider springs in a wrecking yard,and if you grab the shackles and frame brackets,it might not be too tough to just change the whole set up to the older truck.  The problem I see with going to later axles,frame conversions,etc. is that the wheels will stick out too far. If you go with a cab & chassis,you might cover it by going to a 2 ton front group (longer hood,wider fenders,still fits the smaller truck cab),but it'd be a bit of work to make it all gell. If you do it,PLEASE don't change it over to hanging pedals-that just ruins the character of the truck.

 

Agree completely about the track width issue.  These projects are always difficult to sort out.  If I want a '67-'91 era GM beam axle 4x4 truck or a K-model Suburban/Blazer to restore, that's another story, I'd stick with the later body type.  The 292 inline six is a great fit into a vintage Advance Design chassis, and it offers a 7-main bearing improvement.

 

   After I ruined the second rear end on my '57,I used a rear end from a '74 Chevy 4X4,with my stock springs,the newer u-bolts and spring plates,and I made some shock mounts to use my old shocks. The '57 driveline bolted right up. It was MUCH easier than I was told it'd be. (wrong spring spacing,wrong spring width,wrong this,wrong that,etc. There USED to be an outfit that sold a roller bearing kingpin kit that was GREAT,but they're not around now.

 

Interesting that GMC used Spicer 44/45 axles when Chevy used the Corporate offerings.  I had a '60 GMC pickup (SWB step side) with a 305 V-6 and Spicer 45 rear axle with limited slip.  The limited slip diff was prone to ring gear bolt loosening...GMC maintained its own identity until the late 'sixties, these trucks stood above the Chevrolet offerings.  With the disappearance of the 305 V-6 offering, GMC became a Chevrolet with a GMC badge.  (I worked for a Chevy dealership at Coquille, Oregon years ago.  We saw a spanking new '77 Chevrolet pickup come off the transport with a GMC steering wheel and GMC tailgate badging in place!  They each came down the same assembly line, and apparently the parts got mixed.)

   

   Also,(and I'm not sure one is offered for a 3/4 ton) a tapered roller wheel bearing conversion seems to make these ol' trucks drive better on the highway. You MIGHT be able to work up a conversion if you're in good with someone at a bearing house.

 

There have been part number conversions between ball and tapered roller wheel bearings.  The "kits" were simply replacement bearings that happened to fit the I.D. and O.D.  Tapered rollers are a distinct gain, though GM light trucks and cars survived the "New Departure" versus Timken patent for many years.  Adjustment methods and wheel bearing lubricants are distinctly different between ball and tapered roller wheel bearings.

 

   If you score that truck,get logged on with "Stovebolt Forums".

     http://www.stovebolt.com/ubbthreads/ubbthreads.php

(If it's a GMC,it's "oldGMCtrucks.com" .) Better yet,log in on both-Lots of good information and good people there.

    They have a lot of information on conversions to disc brakes,etc. In the Gallery are some pics of some trucks I've owned.

 

Disc front is a definite advantage.  Rear disc is an option...In the case of vintage rear drum brakes, a four-wheel disc conversion would make sense.

 

    I towed a 35 foot 5th wheel RV a lot with my '57 GMC pick up. Even being a half ton it did fine. (I shut down a Ford one ton with a similar sized trailer between Immigrant Summit and Battle Mountain,he backed out of it at about 80,I ran it up to about 90 before I let up.) ONE thing you'll want to do is get a pair of 16.5 wheels and 9.50-16.5 tires for towing. I noticed they make the truck rock-steady with a big trailer.  Also,make damn sure your trailer brakes are working right. I'm not sure my trailer brakes EVER worked,and the pick up's brakes worked fine unloaded,but doing all the braking for a trailer that size gave them a working life of about 100 miles.  When I brought the trailer from Elko to Reno I wasn't too worried when the brakes went bad,because I knew the road very well,but on the move from Reno to Boise,it was a different story. I discovered the brakes no longer did as I was pulling off 80 into Winnemucca. I didn't have the time or the money to go through the brakes so I just bashed on,regardless,with my ex,Dawn,leading the way in her '79 Mercury Zephyr,using her CB to tell me what was coming up-idiot drivers,steep grades,cattle,etc. I didn't know the trailer was as heavy as it was. On THAT trip I had to skip the 16.5's,as they were showing wire and I couldn't find used tires that size. I ran E rated 215-85R-16's on all four corners,and between Caldwell and Elko TWO of 'em started to blister;once I got to Elko another one threw tread. APPARENTLY,this size,even E rated,was too small for the load. After that,I started running 235/85R-16 E's,and never had another tire problem. I DID have to replace the 347 V-5 (3 dead cylinders) with a '68 Pontiac 400,and grenaded two rear ends,one towing the RV out to storage (Exploded the spider gear case,bent the pinion shaft,cracked the punkin.)and one just pulling away from a traffic light on my way home from work.(broke the ring gear in 5 pieces,none stayed secured. It was so weird-pulled away from the light,shifted to third at about 2500 rpm,let the clutch out and it just coasted to a stop,still idling in gear. Got out and looked under the truck,driveline still spinning smoothly..... :huh:

 

Visions of the 347 V-8 and other vintage equipment is vivid.  I owned a '55 Ford F100 pickup for seven years and went through three engine iterations.  I did the Ford Y-block approach (312 with ECZ heads) and two GM engine swaps.  My first GM conversion was a '57 Pontiac passenger car 347 V-8, rated 270 horsepower and fully capable of producing it!  (Did a mate-up to the Ford 9-bolt side cover 3-speed manual transmission and later played with a dual-coupling Hydramatic.)  I was totally engrossed in Pontiac engines at the time and read Smokey Yunick's book on Pontiac V-8s backward and forward.  The last engine change was a Chevy small-block V-8 build that was much cheaper to keep than the bulky Pontiac engines.  Loosening the press-in rocker studs was far less likely on the Chevy engines!  As a point of interest, GM also fiddled with the Oldsmobile V-8s in '50s medium duty trucks.

 

   Speed

Share this post


Link to post
Share on other sites

Speed...Regarding tapered roller front wheel bearing conversion kits for vintage GM trucks, I do recall the narrow spacing for the outer OE ball bearing, so the conversion kit's "custom" tapered roller and race make sense.  For the stock ball bearings on the truck fleet I maintained, the option was the "Micro Nut", a fine tooth locking nut arrangement available in the aftermarket that resolved the questionable factory specs, which varied between the OE shop manuals and added to the confusion.  

 

Directly from the 1955-59 GMC truck factory shop manual for a 100 Series GMC truck:  "rotate wheel and torque spindle nut to 45-65 ft.lbs. then back off nut 1/6 turn (optimal), or as slight as necessary beyond 1/6 turn of the spindle nut".  1958 Chevrolet truck factory shop manual neglects to mention backing off the nut and simple shares the torque spec of 45-65 ft. lbs. for 1/2-ton trucks, which I'm sure fried a lot of wheel bearings!  Passenger cars and the older Advance Design light duty 1/2-ton trucks were 33 ft. lbs. then back off spindle nut to the first slot (approximately 1/12 to 1/6 turn range, which makes better sense and was a spec worth acknowledging for the lighter 1/2-ton trucks).  Your big 350 GMC should have tapered roller front wheel bearings and a different adjustment spec than the light-duty trucks.

 

Ball bearings, unlike tapered rollers, have no tolerance for looseness or play.  I retrofitted each of the GM light trucks with Micro Nut adjusters.  This enabled precise torque settings (actually a slight bearing preload adjustment provided with the Micro Nut specs) on the ball bearings.  By contrast, tapered roller wheel bearings require "end play" adjustments like 0.001"-0.008", they're easier to adjust and maintain.  By 1962, GM abandoned the ball front wheel bearings and opted for tapered roller bearings.

 

The big Caddy V-8s were terrific for reliability and massive torque.  Lower compression smog era, they still produced great power and could run on unleaded regular! 

 

When I played with Toyota FJ40 Land Cruisers, which ultimately led to writing the Toyota Truck & Land Cruiser Owner's Bible, Cadillac Motor Sports was a popular option to the common Chevy V-8 swaps.  When owners wanted serious torque, they turned to these big displacement Caddy V-8s, the Turbo 400 was a natural, and a manual transmission conversion was possible.  (A pilot bearing bore would be essential for that approach!  See you local machine shop.)  As for a 472 Cadillac engine in a Chevy pickup, this had to be a conversion.  454 or 396/400 (big block) maybe, not a Cadillac.  If a Cadillac, the truck would be a museum piece or collectible.

 

Good luck with the dentist!

 

Moses

Share this post


Link to post
Share on other sites

"When I played with Toyota FJ40 Land Cruisers, which ultimately led to writing the Toyota Truck & Land Cruiser Owner's Bible, Cadillac Motor Sports was a popular option to the common Chevy V-8 swaps.  When owners wanted serious torque, they turned to these big displacement Caddy V-8s, the Turbo 400 was a natural, and a manual transmission conversion was possible.  (A pilot bearing bore would be essential for that approach!  See you local machine shop.)  As for a 472 Cadillac engine in a Chevy pickup, this had to be a conversion.  454 or 396/400 (big block) maybe, not a Cadillac.  If a Cadillac, the truck would be a museum piece or collectible."

    I'm wondering if a thin bellhousing spacer and a "bolt on" pilot bearing that attaches via the flywheel bolts and "cups" the end of the crank for alignment might be possible. Not having a Cadillac motor sitting in front of me,it's hard to tell what could be done. I just hate the idea of pulling the crank out of a good running engine to get one hole machined in it. I can see that becoming the start of a classic "Money Pit". ("Do I stop here? Put in new bearings? Maybe I should do the rings while I'm this far into it. Well,might as well get the valves done too;since it'll all be apart anyway,this'd be the time for a trick valve job,maybe a cam and lifters......")

  Speed

Share this post


Link to post
Share on other sites

Speed, as they say, "Great minds..."  You guessed it.  I went to the Cad Company website.  They offer a manual transmission pilot bearing solution.  It's their own billet flywheel.  Here's the statement:

 

Transmissions

 

Why spend hours cutting boiler plate and home-building a plate to bolt your Cad to the Chevy TH-400? You only need to give us a call, order the Transmission Adapter Kit, and have at it. Takes a few minutes to take it out of the box and bolt in on! Got a Power Glide? Got a TH-350? Noooo problem. Call us up and tell us you want the flex plate with the multi-pattern for TH-400, TH-350, Power glide and even the 700R-4. We can even setup one with other TC bolt patterns, such as Ford or Chrysler, on request (but then you're on your own for the tranny adapter). Wanna run a clutch setup, so you can torque test your 4-speed (or 5 or 6 speed…)? No problem again. Call Cad Company and order up a Steel Billet Flywheel and Oilite pilot bushing (featuring a 166-tooth ring gear, for a standard Caddy starter, and no custom machine work required to install the pilot bushing).

 

 

So if you can afford the flywheel, you get to keep the engine intact.  Apparently, they have ingeniously incorporated an Oilite pilot bearing in the flywheel.  Here's a link to the website:  http://www.cad500parts.com/catalog/page5.htm

 

What intrigues me is the scope of interest that still exists in an engine that has not been produced since the mid-'seventies!

 

Moses

Share this post


Link to post
Share on other sites

Hey-the GOOD stuff lives forever. Look at the ol' 392 Hemi-the people who love 'em keep finding ways to keep 'em running. I know a guy who ran a Stude on the salt flats,and he ran a 392 in the car and another in the '64 Dodge 700 car hauler (as a spare in case he hurt the one in the racer on the Salt Flats). The car ran 267.??? pretty consistently,but this was back in '80 or so. His race block had been welded back together so many times both sides of the block were made of steel plate. It sure was a fast car for the little money he was able to pull together to run each year.

   On the Caddy motors,you can use a BOP manual bellhousing with no mods. BTW-you can run a BOPC transmission,GENTLY,on a Chevy engine,or a Chevy trans. on a BOPC motor,if the need arises;the alignment dowels and two bolts will match on any combination,but this strictly a "Getcha home" measure. Flywheels/flex plates,not so lucky,though I've messed with a conversion kit that would allow a standard Chevy 168 tooth flywheel and iron bellhousing (with a T-400 adapter) and 3 bolt starter,to run a Cadillac engine in a truck,but it looks like these guys have a better arrangement. My idea might be stronger on work trucks,trailer pullers and Ton or bigger trucks. I need a Cadillac crankshaft to see if the bolt holes match (I doubt they will) and to make a jig to build a spacer that can fit whatever center hole diameter it has to fit,maybe drilled for a dual pattern if the bolt holes are different. There are so many things hat have to be the same for this to work, If everything fell into place on the Cadillac motor,there's a chance this could also work on Buick,Olds and Pontiac motors.

   Speed

Share this post


Link to post
Share on other sites

I knew about the BOP bellhousing/converter housing share with Cadillac.  The issue is the pilot bearing.  It would be good to see how Cad Company pulls this off.  I'd not get creative with a flywheel improvisation.  A locating ring or lip must clearly secure and center the flywheel to the crankshaft flange.  Can't rely on bolts for centering, even with shoulders.  They're not an interference fit.  Any out-of-center for a flywheel could be lethal...

 

Moses

Share this post


Link to post
Share on other sites

I agree with the center hole needing to be "perfect" sized for it to work;likewise the bolt pattern would have to be  right,the offset from the block would have to be right-there's just too many things that have to be "just right" to hope for an easy conversion unless it's to work for one specific engine. Still,could have been pretty cool,if only......Besides,those truck bellhousings are getting hard to find-I only have a couple left.

   Speed

Share this post


Link to post
Share on other sites

Apparently there IS a pilot bushing available for the Cadillac engines.

 

       cadcologo-sm.jpg

Transmissions, Parts, and Adapters

 


Billet Steel Flywheel for standard clutches $380
Uses stock starter.
Fits most 10” through 12” car/ light truck clutches.


Cadillac Pilot Bushing For manual transmission $45
Fits existing machined hole in crank -
No crank removal or precision machining required in most cases.
For standard GM car/ light truck input shaft size.

Share this post


Link to post
Share on other sites

Wow, Speed, wonder what the Cadillac precedent was for the pilot hole in the crank?  A manual transmission Cadillac of the 472/500 era is non-existent.  Maybe this engine saw additional use in out-of-country trucks?  More likely it was easier to machine the crank with a pilot bore to center the back end of the crankshaft.  If so, nice that they have a useful pilot bearing O.D. for the bore size.

 

Are you working your way up to a 472 or 500 Cadillac swap into the GMC 350?  Take steering gear clearance into account, I'd like to know if this is practical.  The SM420 would fit the pilot, what's the input shaft size on your Clark 5-speed?  Wonder if the BOP flywheel fits the Cadillac crank flange or whether you're back to Cad Company's billet flywheel...Curious if the $45 pilot bushing is a bearing or bronze bushing, would guess the latter.  If so, perhaps the I.D. could be sized to match the Clark input shaft.  Advance Adapters has a shelf full of bronze pilot bearings if you know the sizes.  They can even size a bushing to fit.  Issue here is Oilite material, a necessity for longevity...Also, the bushing material must match the input shaft hardness/design.  If sizing is not an obstacle, a caged (greased and shielded/sealed) bearing with the correct I.D. and O.D. could bridge this gap.  The I.D. would need to be a somewhat interference fit on both the input nose and into the pilot bore.

 

Moses

Share this post


Link to post
Share on other sites

Do you have '55-'59 Chevy V-8 iron truck housings with the rear motor mount flanges?  This was the missing link in many engine swaps...

 

'60-'62 used the right hand release lever for the hydraulic clutch (dual clutch/brake master cylinder).  Did that iron housing also have mount pads?  Or was the rear mount under the transmission like later applications with the aluminum housing?

 

Moses

Share this post


Link to post
Share on other sites

All my iron bellhousings had the mount pads;I used one with the hydraulic slave cylinder and used a "gutted" brake master cylinder to power it and built a mount for it to connect to the floor pedal, (I also learned you can use a mechanical linkage bell housing with a hydraulic clutch by cutting a piece of 2 inch angle,drilling the holes for the stock slave cylinder and drilling two holes to match the two flywheel shield bolts behind the oil filter,and mounting the slave cylinder on the bracket so it kinda fits around the oil filter. I used that set up for about 9 years,so it's plenty strong. Since then,I found that a complete system from a Datsun or Toyota works better than the home-built master cylinder,unless you're using a Borg & Beck or Long style clutch. (They'll still work okay,but figure on rebuilding the hydraulics a couple of times per year due to the excessive pedal pressure.) On my '57 Jimmie I ended up using an aluminum housing because nobody makes an iron bell housing for the BOPC pattern. I used the newer clutch fork and made a rod for it that had a "J" at the end that fit into the recess where a pushrod would normally fit. (The Chevy/GMC clutch was a pull type;I tried drilling through the recess,but it's hardened metal and my drill bits just shined it up.)

   I think I'm down to one bell housing and V-8 flywheel;I was going to V-8 a '52 Chevy dump truck I got,but I've since found more wrong with the truck than I was told of,so I think I'm going to hand it back to the owner.

   Speed

Share this post


Link to post
Share on other sites

So, there was a GMC V-8 truck (iron) bellhousing with rear mount pads (left side release arm) for manual transmission '55-'59 models with the Pontiac/GMC V-8.  Is this a Holy Grail part?   

 

Moses

Share this post


Link to post
Share on other sites

Not really-pretty much any of the V-8 four speed trucks from back then would have it;the big deal is that this bell housing will only fit Pontiac motors up to '63. In '64 Pontiac went to the BOPC pattern,BUT in '64 ONLY they used the BOPC pattern AND the bell housing mounted starter. THAT is the Holy Grail part. (Also the flywheel and starter for that combo.) I ended up with a '64 Tri-power 389 which I put into my first '62 Chevy shortbed;I couldn't find a proper bell housing so I used an aluminum later one and had a 3/4" thick aluminum starter mounting plate added to it. Wasn't pleased with the fit,the starter bolts kept loosening,and every time I drove the truck I got another ticket. I ended up selling the engine and installed a built 350 Chevy motor with the iron bell housing,truck flywheel and standard six cylinder hydraulic 11" diaphragm clutch,with the left side slave cylinder mount I described earlier. (I probably should have shortened the line,since it used to go clear to the right side,but I just looped it a couple of turns and tied the loops to the firewall. Laziness rules!) Worked great,made good power,had a nice choppy idle but still made lots of torque from 800 to 5,000 rpm,and just like the rest of my trucks,it got 10 mpg no matter  WHAT I did.

   Speed

Edited by Speed
fixed a mis-spelled word.

Share this post


Link to post
Share on other sites

I don't know if this is the right place for this,but I'm putting the '54 GMC up for sale:(. I'd love to keep it,but I need money more than I need the truck now. It's advertised on Craigslist Reno,SLC,Boise,Vegas,Sacramento and Bay area for $4,000.00. I'll knock a few bucks off for members of this Forum. Time is short,so contact me at sk8080hd@yahoo.com-the creditors won't wait.

Speed

Share this post


Link to post
Share on other sites

"Are you working your way up to a 472 or 500 Cadillac swap into the GMC 350?  The Caddy swap crossed my mind, I think I'll leave it as it is for now though. Take steering gear clearance into account, I'd like to know if this is practical. 

The 350 Ser. has a wider frame,but I haven't measured to see how it all shakes out.A friend suggested cutting the column just outside the firewall,adding a u-joint and using a cabover steering box with a longer drag link to make some clearance where it'd normally be tight,but I don't know how seriously he researched it out.

The SM420 would fit the pilot, what's the input shaft size on your Clark 5-speed? The Clark was an option on this truck,so I'm figuring it'd fit the same pilot as the 420 does; If not,it won't take much to get a pilot bushing/bearing that'll work. I can even find a clutch disc that'll work. clutch   Wonder if the BOP flywheel fits the Cadillac crank flange or whether you're back to Cad Company's billet flywheel...I'd just use the Cad flywheel as there are so many variables in trying to use a BOP flywheel. Curious if the $45 pilot bushing is a bearing or bronze bushing, would guess the latter.  If so, perhaps the I.D. could be sized to match the Clark input shaft.  Advance Adapters has a shelf full of bronze pilot bearings if you know the sizes.  They can even size a bushing to fit.  Issue here is Oilite material, a necessity for longevity...Also, the bushing material must match the input shaft hardness/design.  If sizing is not an obstacle, a caged (greased and shielded/sealed) bearing with the correct I.D. and O.D. could bridge this gap.  The I.D. would need to be a somewhat interference fit on both the input nose and into the pilot bore.' My experience with a caged bearing in a pilot application id that you can't install an engine with one unless EVERYTHING is PERFECTLY aligned.

BTW,I have to tow that 40 foot semi trailer from White Rock to Last Chance Road,so I unbolted the flatbed and hopefully Tomorrow Ben will lift the bed off the '54 with his forklift. Then I'll drive it up to my house and install the 5th wheel plate (from my '45 Mack-an original articulated 1945 Dayton hitch) and get it ready to work. (I need to fix the stop lights tie some wiring up and maybe run some carb cleaner through it.) I  SHOULD get a trailer plug wired in too. I'll do that,and find an RV 7 blade to Commercial plug adapter if I have time. I might as well-it looks like I'll be needing it often. I already got an offer to tow a double wide from a few miles West of Elko to a place out in River Ranch,,two trips,about160 miles total. Even though it'd be fairly good money,I'm gonna pass. I know the guy who's doing this deal,and I see SO many possibilities for disaster. I finally convinced him to get the Title for the '69 Cornbinder 1800 trailer mover he traded into,get the injector pump rebuilt,throw a used set of rear tires on it that still have tread and just move it himself. Then he won't have to hire a truck and driver. (He has a CDL,all he has to do is get his endorsement for oversize loads.)

   Speed
  

Share this post


Link to post
Share on other sites

Speed...Decided to keep the 350 Series truck?  Sounds like the direction you're taking.  Couldn't find a buyer, or have you simply changed your mind?

Moses

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now