Fixed! After consultation with Bill Hanlon I found that I had continuity from the plug tabs to the ends of the pigtail. I then sprayed inside the plug with contact cleaner and reinstalled it. It works now. The near 60 year plastic insulation is not interested in bending, so I believe I will try the heat tubes on each of those wire.
Thank you, Bill and all others who offered advice!
1950 GMC 100 Panel Truck, 1958 270, 3-spd Saginaw with BW OD, 3.73 12 Bolt Differential from a 1966 C10, Front Disc Brakes Hill Holder Bought it in pieces 9-1976, driving since 6-1978 Follow in the DITY | 
