'65 Dart GT

Welcome! That's a beauty! Your base timing will probably be happy at 10° BTDC. As long as it doesn't ping you are golden. I have always loved that medium red color.
Mike, I believe it still has the factory "special" California CAP distributor. From what I remember reading in another thread it is to be 5 degrees ATDC because of the funky curve. Could be misremembering though. Being a '65 with the timing indicators on the passenger side I haven't had any helper to open the throttle to see what the total timing is.