The alternator I got looked like the old one,it was all a visual thing..the old alternator was worn and beat, had it tested and it was bad. so i told the parts guy i needed a alternator for a 66 Chevy 327 2bl. For argument sakes how would i know if i needed an alternator with an external volt. regulator?would it not have the DA wire plug?I can return the alternator and get another one, but what should i get?.... The only reason why I disconnected the alternator and started the truck was to see how much damaged i caused after the smoke show.