After we found some extra power by installing this simple plastic ring, we began to wonder if maybe a carburetor would benefit from the same. But Holley includes this ring only as an adapter; it's not supposed to make extra power. Carburetor experts and racing engine builders George and Bob Vrbancic both think the extra TBI power came from the fact that a throttle body normally chokes airflow into itself because of the large injectors that hang directly above the venturi bores. Unfortunately, you cannot move the injectors any higher to increase airflow because that'll cause the fuel to spray outside of the venturi. So, instead you can try to improve airflow into the venturi by smoothing its entrance. Apparently, this plastic ring accomplishes that. And installing a tall velocity stack, which has been the normal way to improve airflow into carburetors for years, added just a little more power still, further proving our theory.