If you see the brass shaft, and quick-adjust weight stops, it is the Mallory design, and you are pi**ing into the wind. I can't remember when they went to that, but it was just about the time when Chrysler's Indianapolis Electrical closed up and they could no longer source the OEM design. Late '90s, maybe?

At the time, I thought "great, how much easier....", then the dirty truth was revealed, backed up by a decade of dyno tests and trying to tune street cars.

What do I do now? If you don't want to go aftermarket (Fire Core, etc.), then use a reman stock '72 distributor for your app (A, B, RB) and tune the old PITA, but rock-solid way.

Rick