The Edelbrock 9904 Remanufactured Performer Series 500 CFM manual 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 Edelbrock 9904 Remanufactured Performer Series 500 CFM manual 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 that's reliable, user-friendly and is easily tunable for miles and miles of trouble-free operation.