Why wont my alternator charge

It could just be because a 65 alternator is not correct for an 85 model.
No but the newer alt should work on the older car and if I ground the the 65 alt it should work in the 85 Is that correct but back to my question I wasn't asking if I could use one alternator in the other vehicle and vises versa I was asking if it could be something else other than a voltage regulator that would cause the 65 dart TN not charge thanks for you time.