Rev limiting with a GM HEI module

Anything that hooks "traditionally" to coil neg. "should" work OK. All they do is short the coil neg terminal to ground when the limit is reached, thus preventing the ignition module or points from pulsing the coil.

Some work better than others, and I have not kept up with them. Years (YEARS!!) ago, Autometer had a separate "can" that I believe actually contained a relay. It was a horrid thing.