Waay back in the day the Grump would set up his distributor with ever advancing springs to over 10,000 rpm. as the rpms went over 7000 the timing (with points) would start retarding (set 36 at 3000 at 7000 it was 33) why I don’t know maybe flex, coil slows down, ??? Maybe the electronic stuff handle it better now but imo it’s all about the fuel, good octane run full advance.
I’d have to go back and read what Jenkins said about why the curve kept going, but electronic ignitions are far worse for RPM retard than points.
