Alright, no Ford expert I digress.
But, I'm helping a friend, I hope. 1970 Ford Ranger, 302, Externally regulated motorcraft 65A alternator.
Truck will start and not charge. Rear of bearing housing is not magnetized. Take a test lead and jumper the A+ yellow wire on the regulator to the FLD (field) on the alt and voltage will jump right up to 17.25v. This maneuver bypasses the reg. OK
Now, remove the jumper and the voltage stabilizes right at 14.5v and begins charging.
Shut down, start back up... sometimes it charges- sometimes it does not.
Repeat above steps and charging resumes...