I'm starting to wire my 51 truck. It has a 350 crate engine. The plug to the alt. wont fit my alt. The Wiring kit came with a plug in for the alternator that won't fit mine. The kit plug had two connects but my alt. has 4, one larger and three smaller.
Sorry, don't know. It might help if you are able to identify what model alternator you have. Here is a web page that may help. http://www.rowand.net/Shop/Tech/GmAlternatorIdentification.htm I also used a American Autowire kit for my truck and thought it was exceptional. My alternator only has two wires. One to the battery and a second one that runs through a resistor to a switched +12v (accessory). Some sort of exciter circuit.
American Autowire Question I think the wiring harness is for a "one wire" alternator and you maybe have an alternator that requires an external regulator, hence the extra connections on your alternator. I used a Ron Francis Harness and it had a connector like you do with the American Alternator. Fasteddie1017
