4 vs 6 HELP???

The Jeep 4 uses the same bellhousing pattern as the GM 4s and small V6s. The Jeep straight 6s use an AMC pattern that is totally different.

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The Jeep 4 uses the same bellhousing pattern as the GM 4s and small V6s. The Jeep straight 6s use an AMC pattern that is totally different.

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Hmm, are you sure about that? I know there was GM 4 bangers used in the CJ, but I thought that the YJ 4 banger was the same as the six. Hmm, what year is the YJ? Maybe the '87-'90 YJ 4 bangers have a different pattern than the 258. The later fours seem to be just 4.0L minus two cylinders so I would suspect that the bolt patterns are the same. I guess I'm not much help, but I am curious about this.

jo-jo
'77 CJ5 Fozzy Locker
20 degree RTI 1250

Jo-Jo is right. They did use GM 4's in some CJ's (the 151 Pontiac Iron Duke) but the AMC four does share the same bolt pattern as the AMC 6. Call Advance Adapters and they will be able to tell you all you need to know.

Scott C

The early 2.5l/151cid GM engine used in Jeeps had a bellhousing pattern that is the same as the smallblock chevy. All Jeep/AMC 2.5l 150cid 4cylinders have the later style GM bolt pattern (2.8l V6, later 4 cylinder, FWD 3.8lV6 etc) The 4.0l shares pistons, rods, valves, valvetrain, and front end accessories, but not the bellhousing pattern with the 2.5l. AMC tried to keep the pattern the same so they could use the same transmissions in the XJs with 2.8l V6s and 2.5l 4s (AMC was good at keeping things interchangable).