Cherokee engine in Wrangler

Could this be done with no problems at all. I ask because im intereted in buying a jeep and the guy says he put in a used cherokee engine to replace the high mileage stock wrangler engine.

Theres no difference between a xj and a YJ 4.0 I6 that i know of. the early xj's had a v6 but it was a chevy engine and i wouldn't suggest it. just make sure if you go with a 5spd use a ax-15. The AX-5 is shitty and can't handle a 4.0 hence there only with the 2.5's so if you buy a cheerokee 4.0 make sure it goes into a 4.0 jeep so you have the right tranny or just swap the tranny out too.