93 K10 4.3 To 5.7 Swap. Computer????

I Swapped A 5.7 Into My 93 4x4 W/ A 4.3 And 5 Speed What Computer/prom Do I Need. I Tried One From An 89 4x4 5.7 5 Speed It Did Not Work. I ALSO TRIED ONE FROM A 93 4X4 5.7 5 SPEED IT DID NOT WORK EITHER, THE CONNECTORS FROM THE HARNESS TO THE COMPUTER WERE DIFFERENT.

You could try
www.fastchip.com
They might be able to reprogram the chip that was already in there. Another website to check out is
www.tbichips.com

Did you swap the entire computer or just the chip because you need to change both. Also did you change to the 5.7 throttle body. The injectors have a different rating than the 4.3.

i just got thru swapping the 4.3 for a 5.7 in my 90 chevy 1500 short bed 4x4 now my shift light comes on in 5th gear??????