There's a cpuple companies that make an ignition box with a rev limiter built in.
FBO is one, Rev-n-nator is another.
Do you know if the Rev N Nator is still being made? It says out of stock on the site unfortunately. The issue with the FBO is that it doesn’t have the ability to limit lower than 5200 RPM. Does anyone know if the “Pertronix 600 Digital Rev Limiter” would work inline with the orange box?
