2 rare options on the sheet in the glovecompartment???

[hrc200x]

I've sorta come to the conclusion that Chevy did too many different things to keep track of. I'm trying to update the wiring in my cab with a '84-'86 wiring harness. The Story:

About 5 years ago I bought a rusty '75 chevy 4x4 1/2 ton no major options except dual tanks. I bought a rust free cab from texas which ended up being a '83 cab. Just to get the truck able to drive I had to put all my '75 wiring in the '83 cab. Now I'm wanting Intermitent wipers, power windows/locks, headlight dimmer on the colum, windsheild wipers on the column, basically all the updates with the newer wiring harness.

Today I looked at all the possibilites of different wiring I could use and concluded that I need a donar truck with all the stuff I need, no more trying to swap parts from a Burban, pickup, etc.

My '75 wiring that goes to the starter has a wire that runs back to the fuel tank valve which I think is for the gauge from each tank. Then on the newer wiring it has only like two wires back to the tank vavle, I could just use my '75 wiring to the starter and everything should be fine except outside the cab on the fuse block the same patch of wires that run to the starter also have wires out of it that go to the wiper motor, and if I want to run updated wiring under the dash with delay wipers I'm going to need a new wiper motor, which means none of my '75 wires for the wiper motor will work. Sorry for the rant. I wish I could find a decent wiring diagram? anyone?