you would probably be better off converting the car to OBD1, you generally keep the OBD off the engine. An OBD1 motor is going to be missing the crank angle sensor that OBD2 needs, so you'd have to fake a signal to the ecu.

Also you would need to change the location of some 02 sensors, and probably some other stuff.

I think people would tell you to get an obd1 ecu, and obd2 -> obd1 conversion harness.

You're not going through california emissions, so you probably won't have a too stringent visual inspection, you'll probaby just have to pass the exhaust portion. Make sure you have all the 02 sensors running properly, and you have some sort of cat and muffler hooded up, and you'll probably be fine.

-PHiZ