[WYT VNM]

I use the MSD Billet in my 428. I don't remember which spring combination I have in, but I do know that NIETHER is the heavy spring. I get full advance right at 3000 rpm. Had to change out the heavies (which came installed) to get the engine to come to life. I have no spark knock, and it cranks begrudgingly when hot.

I have 10 degrees initial, and use the colored stop for 24 degrees distributor advance. This is a great setup on my engine.

I can't answer why yours would advance so fast; call MSD???? Is it really to much on your engine??