I had a 92 2-door Cherokee w/a 4.0 and 5 speed. It's a great engine. I considered the same thing when I swapped a 250 into my van. Ultimately I stuck with the ford, but now I'm wanted it fuel injected...
If you go this way, I think you should reconsider the OBDI thing though, I'd go OBDII. They built those cherokee classics until at least 2000 so there are ODBII versions.