[Vintage 1954 GMC 350 Truck Ready for Cummins Power]

 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

[Vintage 1954 GMC 350 Truck Ready for Cummins Power]

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

[Vintage 1954 GMC 350 Truck Ready for Cummins Power]

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.) 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.

   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

[Vintage 1954 GMC 350 Truck Ready for Cummins Power]

  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

[Vintage 1954 GMC 350 Truck Ready for Cummins Power]

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.