Ranger6202

Need your guys' expertise. Talked a friend of mine into buying a 96 crew k1500 only to find out later what the "centurion" on the door and tailgate meant. Long story short, he bought it as a mechanic special as it would not start and had other issues, and i convinced him i could fix it no problem. I am pretty much the around town hobbyist mechanic guru for this area for this kind of stuff (LS swaps, tuning, custom wiring, transmission rebuilds, custom builds etc..). Got the starting issue figured out pretty quick (P/N switch on the transmission was messed up). So this particular Centurion has the 5.7 with the 4l80 and 10 bolt rear axle. Not sure what the chances of this are or if it had the 80 swapped into it as some point. What we have found is that the RPO sticker, wiring harness and ecm in the truck are actually for a 5.0 and 60e. We have found the 80e connector had the normal 3 wires modified to adapt so that it would function. But my experience tells me that the ECM needed to be modified for this combo to work correctly. The issues we adopted in this truck is the fuel trims adding about 50% fuel and the torque converter stays locked up. My main question to you all....is it possible that Centurion had the ability to update/calibrate the ecm for this combination? Did someone else throw this 80e in later and mess everything up? According to our scanner, the ecm has the 5.0 VIN# in it. Did they make all these changes and leave the RPO sticker stock from the factory? Thanks in advance