Re: Engine swap???
If you do decide to swap, the easiest is a chevy. The TH400 on the jeep is internally the same as the gm th400, so you get a gm th400 to go with the chev engine, swap the tail shaft that fits the QT TC so you can bolt up all original drive shafts. Motor mounts are available through novak or advance adapters, and of course you have the other assorted odds and ends to work out. check out ifsja.org for lots of info.