Rocket Doctor Posted February 28, 2015 Share Posted February 28, 2015 I see an ad in a recent print magazine from Edelbrock, announcing their 4.0L Jeep I-6 aluminum cylinder head. They mention a lot of "improvements", longer valve stems, longer guides, polished valves, changed the ports a bit, and thick face, but I'm wondering if there's any real world improvement to be had over the stock 4.0 HO head I have in my 98 Cherokee now? Not trying to be a stick in the mud about this thing, really, but if they were going to jump into cylinder heads for older I-6's, I can think of a few that I personally would rather see.....oh, like a big valve, big port 240/300 Ford, or 250, or 292 Chev/GMC. Is this "Jeep" head from Edelbrock something that the stroker motor guys might need? Just wondering............... Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 28, 2015 Administrators Share Posted February 28, 2015 Rocket Doctor...HESCO has also offered an aluminum performance replacement head for the 4.0L and stroker inline sixes. With a bigger camshaft and compression bump, you would likely notice a significant difference with either of these heads. The reference to stem lengths from Edelbrock hints about valve lift increases and camshaft changes. As for any pressing need to change our 4.0L heads on stock engines, especially the 1998-99 engines and head castings that we are lucky enough to have, would offer questionable gains for the cost. On the other hand, if one has the 4.0L late head or earlier head castings with known issues, an improved head design might be a better alternative than rebuilding a poorly designed head. What year 4.0L engines does the Edelbrock head fit? As for why this engine instead of the 240/300 Ford (which I happen to like, too) or the 250/292 GM inline truck engines, there's a very good reason: The 4.0L was in production from 1987-2006 and amounts to something like 4-million engines produced in that timeframe. Nice target cohort for a product that will have a market for many years. Kinda like the Chevy 350 V-8. Moses Quote Link to comment Share on other sites More sharing options...
Rocket Doctor Posted March 1, 2015 Author Share Posted March 1, 2015 Moses, they claim it will fit any of the 4.0 engines, as well as the AMC 258. "Must use" 1991-2006 intake and 1991-1998 4.0 stock or aftermarket exhaust header. They mention using an "appropriate" (whatever THAT means) intake/exhaust manifold combination on a carbureted engine. (port matching, most likely) I DID see one slight snag in the whole mess, and it only affects a few of us, perhaps. Jeg's lists the head at $1504.00 with "free" shipping. Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted March 1, 2015 Administrators Share Posted March 1, 2015 This makes good sense and fits with the Mopar MPI fuel injection cylinder head design. Port match is common 1991-98 "high port". The 1987-90 4.0L has the Renix EFI/MPI and a different (low port) cylinder head and intake design. This would be a good head for the 258 inline six when using a 4.0L MPI conversion. Many do this conversion with a slightly modified (cooling port changes) stock 1991-98 cylinder head, and these cores are abundant. Again, it's a matter of how much engine buildup is involved and whether there's a need for this aluminum performance head...Nice of Jeg's to throw in the shipping. The price is plenty for the head, most can rebuild a stock head plus the lower engine for that price. Moses Quote Link to comment Share on other sites More sharing options...
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