The Edelbrock 9900 Remanufactured Performer Series 600 CFM electric choke carburetor is a precisely tuned, quality-built carburetor that can handle the rigors of daily driving while delivering consistent, reliable street performance from day to day. Several characteristics make the 9900 Remanufactured Performer Series 600 CFM electric choke carburetor an outstanding street performer. The first one is that metering rods are utilized to transition between circuits. The carburetor 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 carburetor removal or fuel draining. Secondly, the carburetor has the unique ability to hold a tune, so once it is tuned, the carburetor stay’s tuned. What this means to you is that compared to other carburetors, the performance remains consistent and the calibration stays unchanged. The lightweight all-aluminum 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 carburetor thats reliable, user-friendly and is easily tunable for miles and miles of trouble-free operation. (CALIBRATED FOR FUEL ECONOMY) Calibrated for maximum fuel economy. Includes timed vacuum ports, EGR and fuel vapor outlet. Not for computer-controlled engines. Comes with the following jets, rods and springs: Metering Jets - Primary .098, Secondary .095; Metering Rods - .073 x .047; Step-Up Spring - orange (5 Hg). Includes carburetors studs and hardware. EGR adapter #1476 sold separately. Use Carb Studs #8008 or #8024 if needed.