I'm swaping out the inline 4 for an inline 6cyl in my 83 CJ. I need to know about motor mount locations as there are a set of 6 holes on each frame rail and the mounts for the 4cyl.use the front 4. I know the engine sets further back because the rear drive shaft is shorter on the 6, and the front shaft is longer. There was a site where a guy had made this swap, but when I tried to get back it was no longer up. He had the info which I read but didn't copy. Any help? BK sends  

You need to swap tranny too because bellhousing is different as well. You have one of the rarer CJ's power by the GM iron Duke (it is actually a Pontiac motor though many think it is a Chevy motor because it share GM bolt pattern) Depending on what year 6 you use I have seen different mounts on motor. Generally with a swap such as this it is best to "test" fit engine in there to confirm needed mounting hardware. For what it is worth, you could drop in a GM 2.8, 3.1, 3.4 or 4.3 V6 and it would bolt up to bell housing in there and you would not need to move Tcase back or change drive shaft lengths. Also for what it is worth all AMC built 6's and V8's since mid 70's have same bolt pattern on bellhousing and AMC did make a 304 V8 powered CJ for several years so it would be a easy swap using stock type parts and V8 is shorter than inline six.  

No, it's an AMC motor. I had an Iron Duke in a Chevy Monza back in 1979 and I liked the cross-flo head design. I would have seen that immediatly and rebuilt that engine for sure! When I bought the six out of a wreck, I got the engine , trans, and xfer case all at once, although I know my Dana 300 xfer case from the 4cyl is good so I'll use it. I can only hope the trans out of the wreck is in good shape, after all it was wrecked while being driven! I built up the 6 cyl. old school style, 30 over, Crane cam, roller rockers, Offy intake and 390 Holley carb. I have yet to turn the key as so many things have to take place first. Because of the new cam and rollers, it has to be able to run for at least 30 min. to avoid cam and lifter damage, so everything has to be right!  

It is strange that it has AMC motor because that means it has likely been swapped. The AMC 2.5 did not come out until 84 with new Cherokee. 80 to 83 was the "duke". Actually the AMC 2.5 is a better motor. The duke was half a Pontiac 301 V8 and AMC 2.5 was  a new engine of sorts based off 232/258 block but it has a GM bolt pattern on engine not AMC because it was meant to replace duke and swap out with 2.8 V6 offered in Cherokee for several years (kinda FYI if you wanted to know) Also the 4.0 was based off 2.5 design with added cylinders and some tweaks in displacement. Also if you coated cam and lifters with a 50/50 STP/30 weight oil mix, you do not need to worry here about the 30 minute thing. If is more a issue with very high lift cams on valves running 300 to 400 lbs open spring pressure which is not what you have here.  

Hey guys, are there higher ratio rockers for the 6? ya i know stupid question, but figure why not  

NaughtyDodge04:
Hey guys, are there higher ratio rockers for the 6? ya i know stupid question, but figure why not

No such thing as a stupid question but it would have questionable value in use here. I would suggest you use money to make sure it is properly geared in axles if seeking more performance as you will get far more bang for your buck there.  

I don't know if this is the  origional engine, would it show up on the Vin?  

If you go to Tom"olejeep'Collins page it gives the vin of every jeep. On my '83 the fourth code number indicates an AMC 150 4cylinder engine from the factory.