Reman the 4.0 and do a 4.2 head and fuel injection swap. Plenty of vids on youtube. You’ll thank me later. I have an ‘84 CJ7 waiting to be restoed.
For a lot of reasons, I would prefer the 6 cylinder. I’ve read about the conversion and I would very likely go that route.
If I can get a functional 304 for sweat equity and some cleanup, so much for the I6.
My CJ7 mainly needs final paint for the tub, a replacement motor, and rewire.
It’s nnowhere as deteriorated as my Willys.However, the little 65 Willys will run.