tach adaptor Wire your tach correctly.
For use with MSD Blaster, 5, 6, or 7 series used on factory points ignitions, plastic, tachometer adapter
If you are triggering an MSD Blaster, 5, 6, or 7 series ignition with its white wire or points terminal, then you need this unit. This Tach Adapter will correct the operation of most voltage-triggered tachometers or fuel injection systems that do not run directly off the tach output of the MSD unit.
Sold individually.