Sorry, i didnt make enough sense earlier.
The original harness is the LS1 harness from the Commodore? Just want to make sure i understand correctly.
And your going to use the 411 PCM?
I really like the 12212156 OS. It works with Cable throttle, its the 2002 Camaro/Trans Am operating system.
Dont over think the wiring harness.
All the PINK wires are IGNITION FUSED 12V+ (Ive tested a 5AMP fuse on each wire except the Oxygen Sensor heater wires, They got 10 AMP) Never had a issue.
All ORANGE wires are 12V+ Battery (Meaning they are powered all the time) (7.5 Amp works good on them too)
All Black wires are Ground.
It may seem overwhelming at times but go one wire at a time, and in sections. After your first one it will be a breeze.
Im working on the 2002 Truck harness right now for my 5.3/4L80E swap.