To somewhat answer your question, they are different beasts in a few ways. First the 8625 will run the TBI engine just fine, with 2 injectors, blah blah blah. The 5925 is meant to run the CPFI(spider injector) style of multi-port injection. Is the wiring at the red/blue connectors different between the two, you betcha! Stick to the pcm that "came with" the engine you are trying to run. The 5925 likely will never start your engine in its current state.. HTH

Buddrow