The throttle shaft rotates on sealed roller bearings instead of the body itself. This ensures a positive seal between the shaft and throttle body, eliminates wear in the throttle body and provides very smooth operation. Throttle bodies are Billet Aluminum, and available in sizes of 2 1/2", 2 5/8", 2 11/16", 2 3/4", 2 7/8" & 3.0" in diameter. One piece throttle bodies and linkage arms are CNC machined of Billet Aluminum providing a safe and light weight unit. These throttle bodies come complete with Barrel valve, billet throttle cable bracket, and all necessary linkage.