AMC and Jeep interchangably questions

SJR · Jan 27, 2015

I have a couple engines and jeep parts , a 90 Cherokee 4.0 with a Automatic, and a guy I know has a older AMC carbed inline 6 with a manual trans, what I need to know is can I bolt up this 90 4.0 engine to the older bellhousing and trans , also can I swap the parts off the carbed engine to the 90 , if not what can I bolt up to this 90 4.0? thanks guys Scott

gear jammer · Jan 27, 2015

From the info I've found on Novak Conversions it looks like they should bolt up.

jimpaget · Jan 27, 2015

The only issues that you might run into is the electrical connections are not compatible.

TreeClimber · Jan 27, 2015

jimpaget said:
The only issues that you might run into is the electrical connections are not compatible.

Crank position sensor is machined into the bell housing of more modern transmissions. So, a fuel injected engine may bolt to a carb'd-era transmission, but it will take some ingenuity to make it run. Been there, done that.

Most AMC engines have the same transmission bell housing patterns, and that continued after Chrysler bought AMC.

The NOVAK website is a useful tool.

junkyard jim · Jan 27, 2015

NOVAK guys know their Chevy stuff. Had to correct them on some errors on their site in the past on Jeep/AMC stuff however.

As for the EFI on a Jeep 6, unless it's a pre '72 6 cyl, everything on the back of the motor lines up fine. The carb intake is slightly different than EFI one so it has to be "massaged" to fit the EFI head. The EFI head bolts on fine though. Leaks a bit if the block is narrow, but that's fixable too.

All AMC 6 cyls are zero balanced with the same crank flange since '72. Same bell as AMC V8.

Eagle requires a minor grinding of the 4.0L block for the front axle hanger. Not a biggie.

Early 6 had the starter on the driver's side which had the smaller bell housing..

Jeepasaurusrex · Jan 28, 2015

All AMC inline 6s and V8s share the same bellhousing pattern as well as motor mount location.

junkyard jim · Jan 28, 2015

Not true! In the full size Jeeps you have to change the frame mounts to swap to/from 6 cyl. CJs need pass side only swapped. '71 and older AMC 6 cyls have a Willys bellhousing pattern. '71 only 258 has the small bell pattern.