Hi Alvin,
Don't be afraid to build your own harness based on some other Chevy product. I used most of a '75 C10 front harness in my just completed'71 wiring. Get a wiring diagram on the doner and go to town. Don't let wiring scare you. I solder and heat shrink everything. Ground wires are your friend.
Considering your set-up, I would think you could use an S10 front harness easily.
best wishes,
Les
