65 dart not charging with new alternator

Shaun what kind of regulator do you have? 70/ earlier which belongs on the car, and ONLY can be used with the alternator you bought, or the 70/ later "flat" electronic one which has a one piece triangular connector on the alternator. If so you need a 70/ later alternator and I (as mentioned above) would aske for a 73/ later to get "square back"

YOU CAN EASILY test it right on the car. Jumper 12V to the single field terminal and it should charge "full blast." The one you removed, can be tested same way, just ground either field terminal and feed power into the other one.

LOOKING at the photo, I am guessing it has been converted to the later 70/ later (which was a roundback with two field terminals) or 72/ later (which is squareback with two field terminals)