Designed to meet the high performance demands of racing competition these units fit Chevy small block and big block engines. These 100% 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 terminals and a low-saturation ignition module. All have die-cast aluminum housings polished to a brilliant billet-look appearance except as noted. NOTE: without vacuum advance: uses nylon lock-out.