This is a new Chevy/GM style HEI distributor module. Perfect for upgrading weak OEM style modules. This module delivers 50% more spark current than a stock module. Increases HP and RPM range up to 9000 RPM (well beyond a stock 4-pin module!). Direct replacement for all "4 pin" modules in any GM large cap style HEI distributor with a vacuum advance, including those Ford / Mopar HEI conversion distributors.