I have a 95 Country that I bought off a freind of mine. He bought it with a blown engine, so he put a 98 ZJ motor into it. As far as I know, he had no problems with plug-ins and such. Just make sure before you drop it in that all your plugs are going to match up, which they should. There's not much difference if any between a ZJ 4.0 and a XJ 4.0 motors. Just my opinon, but I think you should be okay. What year ZJ are you talking about anyway?