The blocks are all the same, it's the heads that differ. Rennix M.P.I 87 - 90, 91 - 99 HO, don't know for shure but I think after 99 the coil(s) is mounted directly on the plugs ie no plug wires.
The short block on all the 4.0L's are the same.
My pos DD
90XJ Laredo 4.0L(now HO) Auto, 6.5"lift, 36"x12.5"SSR's, custom this and that (snorkle, rockers, bumpers, etct), winch, lights, more crap to come.
90XJ Ltd Up Country, Bored and stroked 4.7L I6 Auto,
2.5" lift 31x10.5"Hankook AT's.