OK here is what I was thinking. I have a 91 Sub 2500 with the 4l80 tranny and a 350 TBI. I would like to swap the small block for a big block. Can I use the same wiring harness? I know I will need a bigger throttle body and accessories. The question is will a bigger 454 throttle body plug into the 350 wiring harness? I also assume I would need a 454 PROM for the computer. The distributor should swap over to the big block right? Anyone done this? I want to keep the fuel injection but would like to get the power of a big block.