My project 82 came with a blown I6.
The plan until recently was to get a reman of the same.
My dad has what is very likely a good shape 304 that came in a dead CJ5.
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.