304 to 258


New member
Hello guys! I have a huge question. I have a 79 cj 7 that is a paper weight in my drive way. It has the 304 and was built to perform. Well needless to say the top engine needs rebuilt. But since it's summer, I bought a 258 for a quick swap until the 304 can be rebuilt. Can you tell me if I need to get a new alt or carb? Do I need to relocate the fuel line? Get different motor mounts? I also found a 290 amc..I got the 258 for 300. Anyways, I'm just not sure what to do regarding the swap. Any help would be great

If the 258 doesn't have a carb, most likely you will need one. You will need to run the fuel line down the opposite frame rail from where it is now. One motor mount needs changed and they bolt on so that shouldn't be difficult ,cant remember which side it is. Use the same alt. That should be about it.

258 can be all you need, they do burn the gas,no more then the 304, 258 rebuild is my pick, NP ? 432 four speed granny,Dana 300 w/advance adapter, thats a great set up