304 swap

timgcummins

New member
hey guys i need some ideas for a replacement for the stock 304 in my 78 cj7 it has an automatic and quadratrac im thinking maybe a chevy 350??? id like to keep it as easy as possible
 

The easiest possibility would be just rebuilding your old one and dropping it back in. I have a tj so I wouldn't know what could bolt up to your drive train. But I'm sure a 350 would fit. But rebuilding would be easiest. I'm guessing the knocking coming from your bottom end didn't turn out anything good
 

Find anthor 304, you could prbably buy a running CJ5 and buy it engine and all cheaper than you could adapt and swap with less the hassel. Then make your money back selling off the extra's. Or find an FJS to pull the engine from. 360's are a bolt in if you had a 304.
 
Do yourself a favor and just do a long block swap. The average mechanic can do the job in a weekend; maybe even bump up to an AMC 360.
 

Ive got a decent 304 too. I think it needs a valve jod on the heads, costs about a $100 here, or you could swap your heads onto it.
 
Ive got a mildly built 401 in my cj-7. Way to much power for a jeep in my opinion, but sure is a blast to drive. I may end up puting 36-38" tires on it so I will probably need the extra power then. A 360 would be another option, theyre plentiful too.
 

swap a AMC 390 or 401 fits same as 304.


The AMC 401 is getting pretty hard to find. Most of the major rebuilders need you to send them your block first as they don’t have a rebuilt one in the warehouse. The 390 will be even harder to get. Not saying it can’t be done but it can take a while. I haunted Craig’s List and the like for over a year to come up with mine and then I had to drive to the other side of the State to pick it up. That’s why I suggested maybe bumping up to a 360 as they are still fairly plentiful.
 
i found out that you have to use amc v8s, not dodge v8s. the old amc v8s have a different bolt pattern then the new dodge v8s and they are balanced differently, using the flywheel versus internally balanced so you have to get the correct flywheel also
 
i found out that you have to use amc v8s, not dodge v8s. the old amc v8s have a different bolt pattern then the new dodge v8s and they are balanced differently, using the flywheel versus internally balanced so you have to get the correct flywheel also


Yep, it’s got to be an AMC and you have to use the right flywheel but they are available for any parts house. Look for the motor size cast into the side of the block below the motor mounts.
 
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