1997 4.3 to 5.7 motor swap

[jdbake]

I'm doing a motor swap in my 1997 gmc Sierra 2 wheel drive I'm in the process of replacing my old 4.3 vortec with a 5.7 vortec I have the ECM for it and everything I need but I can't use the old 5.7 wiring harness due to wires being cut and I was wondering what I needed to do to make the 4.3 wiring harness work?

 

[RHamill]

I would eye ball it and make sure all the connectors are the same, especially ECM, maf, IAT, map, tbps..

 

[jdbake]

I would eye ball it and make sure all the connectors are the same, especially ECM, maf, IAT, map, tbps..

Well I've heard that everything is the same that the only difference is the extra wires you have to add but Im not sure what wires to use and all of that

 

[VorTecxas]

Get a harness if you can. It's less of a headache than trying to make yours work. And you have to use a '97 harness, '96 and '97 are on their own with their wire routing to the junction block and PCM, I found that out the hard way