V3NOM GTO

iTrader: (3)

I dont know exactly what the ecu is from( may be stock) but its in a 99 Chevy Truck. The truck has a F1C Procharged 408 and the guy is gettin ready to go to Big Stuff III. Will there be any problem with this working on my 2004 LS1??

poconojoe

iTrader: (43)

Wrong lower connector, yours is green and that PCM requires a red one, if you're using the harness too, you should be all right, but it will have wrong injector connectors on it

psiconversion

iTrader: (5)

The 99 harness will not have the grounds for the O2 heater circuits or some other grounds required by your 04 PCM. As Pocono said, the 99 has red retainers instead of the green ones your 04 PCM needs, they wont fit either since they are keyed differently. Regardless, if the PCM and harness match (whether 99 or 04), they will work with the 04 engine albiet if you change the FI connectors.