Designed and calibrated for optimum street performance in small-block and some big-block engines. Match with a variety of manifolds that include Edelbrock Performer, Performer EPS, Performer RPM, RPM Air-Gap, Torker II and other brands of similar design. Includes both timed and full vacuum ports for ignition advance. Electric choke #1478 can be added if needed. Comes with: Metering Jets – Primary .100, Secondary .095; Metering Rods – .070 x .047; Step-Up Spring – orange (5" Hg).