I read through the whole overdrive post you linked, I had no idea GM did that, guess they knew what they were doing. I ran a Mallory tachometer for years in my race car that had a built in rev limiter. It had twin dials, one for a shift light, one for the limiter. The hookup was simple, one wire each for power and ground, one for lights, and one to the TACH terminal on the HEI. The limiter killed all cylinders at once using the TACH terminal, not sure what it was doing in the module to kill the signal, but it worked really good. If you just hit the limit, it would be a quick on and off till the rpm came down, but if you stayed on the throttle, it would hit hard.
Last edited by Joe H; 11/25/2025 2:32 PM.
