Thank you for your response.
I really would like to modify my original, it seems to be clean and pliable, I haven't found any brittle spots. Car has 99,000+ miles and was garage kept most of its life. I've dissected harnesses before and repaired and re-wrapped them, but only when I had good detailed instructions and schematics. I've got the 70 Monte assembly manual but wondered if there is clearer information out there. Can I use the original and add or move wires? There was also the trio of gauges mounted under the dash so I'm going to have to buy new water temp and oil pressure units anyway.
My car is Autumn Gold with a white painted top. It had a gold bench seat, going to black interior. I've done the headliner, speaker deck, carpet is going in, dash is black, then I found these gauges. 406 small block (mild build), 350 turbo, A/C. I was lucky to find buckets, console, shifter, and harnesses from one car.
Any info I can get will be appreciated.