I am just guessing but I would guess that most all 4.0 from 99-2006 are the same out of grands, cherokee's, and wranglers...but I may be wrong. I found a lead on a 4.0 for 150 with a cracked head out of 2002 cherokee. The guy selling it said he was going to put it in his 99 WJ but it wouldn't be a direct swap because some of the accessories wouldn't bolt up to it...mean the holes were not milled in the block.
I'm scouring the net and all the clubs I know for a 4.0 engine that will drop in my WJ because mine has a hole in the oil pan from internal engine damage.
The seller is getting me the engine code so I can do more research on it, but what else should I look for in an unknown engine with a cracked head...head has been removed so I can see hone marks on cylinder walls.