The "roundback" style was used through 71 and then CC switched over to the button style diodes which required a square shaped reat section. Appreciate all of the kind words. We are car guys first and foremost and simply want y'all to be satisfied with the restored piece. I don't like the thought of having to dodge customers at Carlisle or the Mopar Nationals! I owe a lot to Jules D. for providing a business model, Joe Arsenault(BeepBeep)for his tech support during Dixie's start-up and all of our first 6 month customers who took the initial leap of faith.