EDELBROCK PERFORMER SERIES 600 CFM, ELECTRIC CHOKE CARBURETORS CALIBRATED FOR FUEL ECONOMY Designed for small-block and small displacement big-block engines, these carbs are recommended only for stock to Performer level applications.Calibrated 2% leaner than #1405. Includes both timed and full vacuum ports for ignition advance. Comes with: Metering Jets - Primary .098, Secondary .095; Metering Rods - .075 x .047; Step-Up Spring - yellow (4" Hg).