GlowShift's HEI Tachometer Signal Filter is specifically designed for vehicles with High Energy Ignition Systems, and converts the high voltage signal to a more manageable voltage, that allows the tachometer to easily read.
Note: Note: Any vehicle with a High Energy Ignition System (HEI) will require this HEI Tachometer Signal Filter. Many General Motors vehicles within the range of 1975-1990 come equipped with this ignition style. If your vehicle falls between these years, verify this is the type of ignition system in your vehicle. If so, this HEI Tachometer Signal Filter will be required to gain RPM readings.
Odds are, you need this.
I wish I hadn't glanced over the part that I probably needed this. Wondered for a few weeks why the tack acted up and registered way high! Bought this and bingo, fixed it.
You probably need it to.
Posted by Cray Stephenson on
I installed an HEI distributor in a 1968 Firebird -the HEI signal filter did the job in converting signal to work with stock GM/Pontiac hood mounted tach . I also purchased one of your digital glow tach's just to compair as I had an old Firebird hood tach that I imbedded the Glow Tach into . Digits are a bit small for good view but it works with the HEI too
Posted by Gary Andersen on