Update:
Well...the new Spectra 20gal fuel tank and Spectra sending unit came in today. I installed it and dumped 6 gals of gas in and when I turned the ignition on my fuel gauge shot up to 1/4 tank...so my sending unit is good (woo woo!)
I dumped a bit of gas into the carb (hadn't been cranked in a while, and no fuel in truck at all) and she fired up and purred like a kitten.
Then, as I go to back it off the ramps...rookie mistake kicks in:
My shift pattern was wrong...I had the plates that screw into the transmission to change gears hanging down instead of sticking up so my gears were backwards. After flipping those upwards and tuning my linkage for short-throw shifting, everything was done.
I aired up the tires and headed up the road to the military rifle range/WMA gravel roads and test drive her. Shifting was smooth, and everything worked (heater, lights low & high beam, etc)
Problem still keeping the truck from being road-ready:
However, even with both feet on the pedal pressing as hard as I could, I locked up the brakes and the truck pulled hard to the left and turned a complete 90 degrees pointed toward the left ditch of the gravel road...a clear indicator I'm still not getting brake fluid to my front passenger wheel disc brake.
I disconnected the metal line from the proportioning valve and brake fluid came out there, so I have a clog somewhere in my line(s) going to that one front passenger wheel.
I guess I'm going to heat to NAPA tomorrow and get a length of metal brake line, a tube bender, a flare tool, all my fittings, and a new rubber line to go to the caliper. That should take care of it (I hope).
For anyone who's bent their own brake lines and installed them in the front before, I'm open to any advice. I've replaced metal brake lines that were bought already pre-bent but this will be my first attempt at bending & flaring them myself.
Thanks, I'll keep everyone posted on the progress.