The Edelbrock #12403 Accelerator Pump Cam Kit Assortment Package of 8. These accelerator pump cams will have different shapes and profiles, allowing you to fine tune the accelerator pump's performance to the engine's requirements. Cam "lift" will directly affects the accelerator pump stroke and pump capacity. While the cam ramp profile and/or shape will control the "timing" of the shot. Each kit comes with 8 different accelerator pump cams and will fit Holley 2300, 4150 and 4160 carburetors.