Wiring Question (Probably)

Hello everyone!

First off, I'd like to say hello to everyone in the forum! If we have any Bullitt owners in here, I probably met you way back in the day when I owned an 01' Bullitt after high school. Also owned a '93 Notchback Fox and a '96 F150 so I'm no stranger to Fords. Recently I got the chance to take ownership of a 1999 GT shell for the low price of free.99 (as long as I paid for the cost of towing) and I'm looking into options for modification.

So, I've been on a Chevy kick lately and had been building a 350 SBC in my garage for a V8 S10 swap. But now that I'm taking in this shell, I'm planning to go a different route and dump it in this thing (feel free to flame me, I'm just working with what I got especially with Covid around).

I've got most of the swap covered as far as mounting, fuel/air/ignition/etc. The one thing that's messing with me is the stock wiring harness for the car itself. It does have a full engine and body harness intact, but with the Chevy 350 I plan to run a standalone harness with ECM along with a 700R4 as well. In doing that, I plan to bring the stock harness of the shell itself down to the bare necessities such as locks, windows, A/C, etc. But I'm extremely lost with where to start. I had the whole thing planned for the S10 as it was a 0411 PCM and could be easily flashed to remove any security issues that would come up with the engine swap. But I know Mustangs and their PATS can get a little fickle with swaps.

Does anyone have any links or diagrams they could offer me to give me a jumpstart in figuring out what will be needed, what can be trimmed out, and how I can get the car to still function as it would minus needing to control the engine and transmission. I won't need any cluster functionality as I plan to go with an Autometer cluster panel with aftermarket gauges running off the standalone harness on the 350.

Thanks in advance, and sorry I'm desecrating this Ford with a Chevy engine! Blame it on Covid