Unless the V8 was toast, I don't know why you'd want to put your I6 in it. But you can do it. You'd have to change some of the wiring and computer to do it. You own a 96 so don't even bother with an older one. The wiring doesn't match up at all. The connectors are all different and some are missing completely. It would be allot simpler to look for a 96-98 with an I6. Also, unless you've done allot of work to your engine and the donor is a wreak, it's a waste of time.
[_]☺☺[_] 96' Grand Cherokee Laredo 265,000 miles and still going strong.