The Edelbrock Performer Series Manual Choke New Carburetor features a two-piece, all-aluminum construction for cooler operating temperatures and less warping. It is designed and calibrated for good street performance and fuel economy in the Edelbrock Performer manifolds. There are no gaskets below the fuel bowl level for fewer leaks and no plastic parts or power valves to blow out. The Performer manual choke carburetor includes both timed and full vacuum ports for ignition advance. The carburetors use easily changed metering rods for precise tuning.