I think that the old reg just get old, I mean after 40+ years, they are not gonna perform like new. Almost everything on my car is new and I checked the voltage signal that tells the reg what to put out and it was also good. Like I said the repo batteries can't take that high of a voltage like a lead said battery, ask me how I know. What I did was take a new reg and mad a bump on it so that it looked just like an assembly regulator, then had it date coded for my car. Nobody can tell it from a NOS one. But the big thing, is that my repo battery is happy.