HEI Distributor Racing Type w/Vac-Adv Blue Cap Polished For Chevy V8 Engines Clamshell Pack ProformDesigned to meet the high performance demands of racing competition, these units fit 1955 1982 Chevy small block and big block engines. These 100 percent NEW distributors have all the reliable components of the 66940, but they also include a highpower 50,000 volt coil. This high performance distributor produces a 50,000 volt spark through 7,500 RPM with true spark alignment for instantaneous response, a high performance curve, a premium cap with brass