90 GP harness?

[Mr_Efficiency]

I have an 88 S10 I'm swaping in a 2.8 hybrid motor (3400 top end) and I want to run it off my 90 GP harness and i'm curious what all i need? I striped everything from the engine bay and there are a bunch of thick red, orange, yellow and pink wires that go into the firewall... that was expected, they are constant power, keyed power and the starter etc... but what i didnt expect was there are 15 small wires that also go from the ECM (or the fuse box next to it) and into the firewall. (pass side)

What are these for? Are they just gauges and dash lights? If thats the case i can just chop them and be fine, i just want to be sure there not anything important before i go butchering the harness.

thanks

[Brian P]

a lot of them are signals for the dash lights, speed sensor, brake pedal switch wires, things like that. If you can find a 1990 GM W-body book it will have the details of each wire at every pin, unfortunately my '90 Cutlass book is long gone

[Mr_Efficiency]

thanks, I have a few wiring diagrams but none show pin for pin what each wire does... I can piece it together by color tho.