jdl71 and Blue666(2), thanks for your input to this thread.
My engine harness came from Howell Fuel Injection. I really like their stuff. I've used them for TBI systems for three Jeeps and this truck. Their Jeep harnesses are pretty much made to fit and easy to install. For the C20, I had to either lengthen or shorten about 2/3's of the sensor leads to make it fit right. No big deal.
I also looked at the FITech systems and had a conversation with them. I asked them about their Fuel Command Center system so that I could avoid running a fuel return line. They told me that their Fuel Command Center systems don't support the factory GM two barrel TBI units. Again, no big deal. Ran a return line to a new fuel tank that came with a return line fitting. With a vented fuel tank cap, no gas smell in the cab.
So lately I've been taking care of the more mundane detail work to get the truck fully functional and testing the various and new-to-the-truck accessories.
I've finished my end of the Vintage Air install with the installation of the vent registers and ducting. The next step is the ac shop for system charging.
The dash-to-firewall cavity has gotten somewhat crowded with all the new wiring and ac stuff.
I re-installed the wiper linkage. The Newport wiper motor w/delay works great.
Installed these new LED tail lights. Got them from Brothers and I really like them. This step tests the light fixtures as well as the wiring harness and the Ididit steering column. Running lights, turn signals and stop lights all good.
And finally, I re-installed the original ( I think ) horn and it tested good. Again, this tested the Wiring harness, steering column AND the steering wheel kit.
I have been very fortunate in that, so far, all functions have been coming up without re-work. Reading instructions two or three times, asking the selling vendor to clarify certain instructions, and taking ones time definitely pays off.