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 83645. The coil features special low inductance, high temperature windings which charge faster to give you increased spark energy at higher rpm. The premium epoxy filled construction is designed to withstand harsh race applications as well as the wear and tear that daily usage dishes out, and still deliver more spark energy to the spark plugs. Features: Direct performance replacement for GM HEI coil-in-cap distributors70: 1 turns ratio and lower primary resistance produce high voltage outputFull power sparks to 9, 000 RPM when used with 8364 MSD HEI ModuleRecommended for use with MSD HEI Module PN 8364CARB E. O. ApprovedPit Stop USA offers MSD HEI Ignition Coil 8225 at low everyday prices. Be sure to check out all of our products from MSD including MSD Ignition Coils.