I am picking up a friends `94 GC next week to do some work on. It's got a 390 mag stroker in it. He has had a crap load of problems to get it to run correctly.
Yea the stock OBD-I ECU aren't tunable so you need to trick the ECU to get it to run correctly.
You might want to join thespeedfreaks.net . Its a good site If you want to make your Jeep fast. A lot of good info. We'll try to help you as much as possible to get it to run correctly.