CALIBRATED FOR PERFORMANCE 500 CFM, Square-flange, Electric Choke, EGRDesigned and calibrated for small cubic-inch engines such as 305 c.i.d and smaller Chevrolet; 302 c.i.d. and smaller Ford and dual-quad applications such as Edelbrock C-26, F-28 and Street Tunnel Ram. Match with an Edelbrock Performer or Performer EPS manifold and other brands of similar design. Includes both timed and full vacuum ports for ignition advance. Comes with: Metering Jets - Primary .086, Secondary .095; Metering Rods - .065 x .052; Step-Up Spring - orange.