If you're hanging a common internally regulated GM alternator on your ride, you had better cough up the bucks for this problem solver. If you just wire-up the alternator with any old "parts store" plug you will have a nasty little surprise in store for you... the engine won't shut off!
When wired correctly the alternator will back feed juice to the ignition switch and keep your hot rod running. NOT COOL! This harness fixes that problem and will make you the hero of the drive-in.
This adapter plug does not work with "one-wire" alternators. It is not needed. This adapter plug works with GM alternators with the built-in regulator, typically from 1971 or newer cars and trucks, like our 91367163 or 91067150.