Came out of a thread in the general chat. Here's the comprehensive list of what motors will fit which Jeeps.
1987-1990 Jeep Cherokee XJ 4.0L
Renix motor - you can use 87-90 4.0L
91-01 XJ, 93-98 ZJ, 91-95 YJ, 97-99 TJ You will need to relocate temp sender to thermostat housing from HO motor. Also need to use all your Renix accessories, distributor, flywheel/flexplate, etc. 00-01 is not recommended due to crappy head. Some people say the 0331 isn't as bad as people say. We scrap Jeeps, more than likely if we get a 0331 head Jeep in the head is cracked, well over half the high mileage 00-01 ones we get in have this problem.
1991-1999 Jeep Cherokee XJ 4.0L
87-90 XJ - Renix motor, lower power output, not recommended
91-01 XJ, 93-98 ZJ, 91-95 YJ, 97-99 TJ (read 87-90 XJ section above about 0331 head issues on 00-01 XJ)
2000-2001 Jeep Cherokee XJ 4.0L
00-01 XJ
You can also use 91-01 XJ, 93-98 ZJ, 91-95 YJ, 97-99 TJ engines, but you will need to purchase separate coil pack adapter brackets since the 00-01 is a coil pack motor and earlier engines do not have mounting provisions. It would be cheaper and easier to just find the correct 00-01 motor.
93-98 Jeep Grand Cherokee ZJ 4.0L
87-90 XJ - Renix motor, lower power output, not recommended
91-01 XJ, 93-98 ZJ, 91-95 YJ, 97-99 TJ (read 87-90 XJ section above about 0331 head issues on 00-01 XJ)
99-04 Jeep Grand Cherokee WJ 4.0L
99-04 WJ, 00-06 TJ - 2002 and up were TUPY heads and did not have the cracking problems that earlier 0331 heads had. 02+ are recommended.
1991-1995 Jeep Wrangler YJ
87-90 XJ - Renix motor, lower power output, not recommended
91-01 XJ, 93-98 ZJ, 91-95 YJ, 97-99 TJ (read 87-90 XJ section above about 0331 head issues on 00-01 XJ)
1997-1999 Jeep Wrangler TJ/LJ
87-90 XJ - Renix motor, lower power output, not recommended
91-01 XJ, 93-98 ZJ, 91-95 YJ, 97-99 TJ (read 87-90 XJ section above about 0331 head issues on 00-01 XJ)
2000-2006 Jeep Wrangler TJ/LJ
99-04 WJ, 00-06 TJ - 2002 and up were TUPY heads and did not have the cracking problems that earlier 0331 heads had. 02+ are recommended.
There you have it, please let me know if anything is wrong here. This was all gone off of by memory and experience here in the shop. I think I got it all correct but if anyone finds issue let me know and I'll update it. Also, some motors might have slight wiring differences with the temp gauge wiring because after 96 they stopped putting them in the cylinder head. You can either use a 96+ thermostat housing and extend the wire, or you can drill and tap your existing housing and extend the wires. You can also be brave and drill and tap the head. I'd rather do the housing and extend the wire and not risk it.
There are also some other differences with swapping HO motors into Renix Jeeps and the other way around, most of it is gasket related and easily remedied with using the correct gaskets.
Hope this helps some people!