Your wagoneer is a NT (narrow track) meaning the axles are shorter than a WT (wide track). All J-trucks and some Cherokees were WT, which I believe is 2" wider on each side. You will probably run into the width problem, as well as a wheelbase problem. If you don't mind cutting the frame, shortening drive shafts, and doing alot of relocating, then it's all up to your imagination.
You would probably be better off putting the Wag's running gear on the J-truck...minus the axles which wouldn't fit. Engines, trannys, and transfer cases are all interchangable. You would have to get adapters made for I6 to V8 swaps though.
Check out www.ifsja.org.
The guys on the message forum could help you through anything.