Jeep Strokers

My son asked me this question ( kids always com up with the strangest questions). what can you do to stroke a 2.5? Well I looked and the original engine that AMC purchased for 2 years from GM (82-83) had a 4" bore and 3" stroke. In 84 AMC started to make the motor, which i think is basically the same motor, but uses the 3.875 pistons instead of the 4" chevy pistons. I assume that they also went to AMC rods instead of the chevy rods. The stroke went to 3.19" from 3". So the AMC motor has the longer stroke. So does anybody know if the blocks and cranks were basically the same? The stroker in this case would be to put the Jeep crank into the Chevy block. Bore it over a little bit and you will end up with a 4.7L engine.

My first suggestion was to rip out the 4 banager and replace it with a 4.0L, But then you would also have to replace the trans and trnsfercase wiring and computer. It may make some sense.

No, they're not.

The GM (actually Pontiac) engine used was the 151ci - which also went under "Iron Duke" and "Quad IV" at times.

The AMC version wasn't a version of that engine - it was based on a 258ci with the two centre cylinders removed and the rest shoved back together. It belongs to a large family of one, and it's not something that can be stroked easily (you'd have to have a crank made or offset-ground for it. We can stroke the 242ci/4.0L because all of the "Modern Era" AMC sixes shared many parts, and that gives us two crankshafts with an increased stroke. 3.500" for the 232ci, and 3.895" for the 258ci.)

It is strange that Jeep put a GM bolt pattern on the bellhousing. The more we looked at the project it did not seem to make sense from the dollars spent to the gain acheived. We finally settled on using a GM goodwrench 3.4L V6. It is designed to replace the 2.8L ( like they used in the early Cherokees) in the S10 pickups. The engine is only about $1,800 new and is rated at 160HP. We will have to scrounge the manifolds and accessoried form the boneyard, of find a blown up truck cheap.

5-90 wrote:The GM (actually Pontiac) engine used was the 151ci - which also went under "Iron Duke" and "Quad IV" at times.

The Pontiac "Iron Duke" and the OLDSMOBILE Quad 4 are similar only in the fact that they are inline 4 cylinder engines produced by GM!
The Pontiac "Iron Duke is 2500cc's/151ci pushrod engine, there are two versions of the Iron Duke, the transverse with the small bell housing and the longitudinal that uses the same bellhousing that the big Chivy 6's and V8's use, the one used by AMC has the big Chivy bell housing, I used one of the bell housings to hook a 4.3 V6 to a Ford T-18 in a CJ5.
The Olds Quad 4 is a dual overhead cam engine displacing 2300cc's/138ci @ 180hp, I have one in my '88 Olds Cutlas Calais backed with a 5spd and it'll out run ANY! Iron duke any day of the week!

Hm - must have gotten my wires crossed. Again. I could have sworn there was a "Quad IV" iteration of the Pontiac 151ci engine...

Side question - since I note you're an engine machinist, I don't suppose you'd have prints of the various "modern" bellhousing patterns and an authoritative list of which engine uses what, would you? I'm primarily interested in RWD/4WD applications as research for yet another book I'm working on... Probably patterns used from about 1960-1965 forward, I'd think - that should cover pretty much anything you can find in a salvage yard.

I know about GM using the same pattern on all their "modern" V8 engines, which also gets put on the V6-90, some V6-60, and some of the I4 engines, but Ford is confusing - and I'd like to finally hammer out the imports (I've not found an authoritative source for them as of yet...)