HO in a 90 xj??

If I am right 90 xj's do not have the HO engine in them right?

What do I have to do to put a newer HO engine in an older jeep? Current one is blown so needing to swap, Plenty of newer 4.0's in the yard. Thanks for any help.

If you grab a 91-95 OBD1 might be easier than later years.

Should be pretty straight forward. You will want to use as much of the Renix sensors/flywheel/flexplate so that your harness and ECU/TCU will function correctly.