Pit Stop USA is The Online Motorsports Superstore! Flow Design Carburetor Adapters are CNC-machined for optimum fuel distribution at high velocity. Each Flow Design carburetor adapter is designed to work with the shape of a specific intake manifold plenum and have been dyno tested, flow tested and race proven. Dyno proven gains up to 17 horsepower have been shown over other adapters. We feature Flow Design Carburetor Adapters and Flow Design Carburetor Spacers at low everyday prices.