The Edelbrock 14073 Performer Series 750 CFM manual choke black powder coated carburettor is a precisely tuned, quality-built carburettor that can handle the rigors of daily driving while delivering consistent, reliable street performance from day to day. Several characteristics make the 14073 Performer Series 750 CFM manual choke black powder coated carburettor an outstanding street performer. The first one is that metering rods are utilized to transition between circuits. The carburettor is unaffected by engine backfires, which means that there are no power valves to blow out, and the rods can be changed in seconds without carburettor removal or fuel draining. Secondly, the carburettor has the unique ability to hold a tune, so once it is tuned, the carburettor stay's tuned. What this means to you is that compared to other carburettors, the performance remains consistent and the calibration stays unchanged. The lightweight all-aluminium body features a two-piece body that resists warping and is compatible with gasohol and blended fuels. The simple tub-type bowls and rear-pivot floats all contribute to a carburettor that's reliable, user-friendly and is easily tunable for miles and miles of trouble-free operation. (CALIBRATED FOR PERFORMANCE) Designed and calibrated for optimum street performance in small-block and big-block engines with Performer RPM, RPM Air-Gap and Torker II manifolds and with Performer manifolds on large cubic-inch engines. Includes both timed and full vacuum ports for ignition advance. Electric choke #1478 can be added if needed. Comes with: Metering Jets - Primary . 113, Secondary . 107; Metering Rods - . 071 x . 047; Step-Up Spring - orange (5 Hg). Use Carb Studs #8008 or #8024 if needed.