If not start/no spark key on run, Ignition Resistor? Ballast Resistor?
Circa 1978,79, The Tile contractor I drove truck for had a fleet of late model D 318 pickups. I had a box of ignition resistors with me, and spent many a fine day on long drives out to rescue stranded crews. Turn a few screws, Vroom. Every time. Lunch. Drive home. Good Wrenching!