The L-Panifold is a specially engineered cast aluminum intake manifold for Harley O-ring style Panheads and Knuckleheads. The Panifold features radius corners and a direction “Y” shape inside. This shape helps the flow and delivery of the air/fuel mixture to the combustion chambers. The overall increase in flow is nearly 25% above the stock design!! We have also added clamp stops so the clamps will stay in place as the Milwaukee muscle flexes. The flange will bolt up to any Linkert carb using the standard 4 hole mounting bolt pattern. If you have plumber style intake ports on Bigtwin motors 1940 - 1954 you can buy a steel adapter nipple kit made by Colony offered on this web store to covert your heads to o-ring style. This product is 100% American made!