Oh heck, I plumb forgot about the alternator conversion issue! Bartamos and Gord&Fran are right on. That diode prevents feed back to the coil . Disconnect the plug from the alternator and start your truck. Then turn the ignition to "off" .......if it "shuts off" you've found your problem. I think.
There's another post in this forum by 1954Chevy 5Window who had the same issue, you might check that out as it describes a similar problem, the alternator and diode issue.
Last edited by Dusty53; 10/22/2017 3:00 PM.
