I have a 66 Mustang with a 289, at a recent car show the judge (who seemed to be very knowledgeable about early Mustangs) mentioned that I have a 1972 alternator instead of the correct 1966 model. Physically and electrically I believe they are very similiar but the markings are different. He then mentioned that the 1972 dated alternator that I have is fairly rare and that I could probably sell it on [censored] to someone restoring a 72 and purchase the correct alternator for my 66. Anybody have any comments on this? Are the 72 alternators hard to come by?