HEI owners now have a choice to replace their stock coil with the MSD High Energy Unitized Coil for GM HEI Distributors. This coil is a direct replacement of the stock coil and offers increased spark energy when used with the MSD HEI Module, PN 83647.

The MSD HEI Coil is designed for use with the MSD High Output HEI Module, PN 8364. It will work with stock ignition modules, but for maximum output use the MSD HEI Module.