The Bronze L-Panifold is a specially engineered cast silicone bronze intake manifold for stock 74" Harley Panheads '55 to '65 with stock cylinder height of 5.330". The stock height cylinders on a 74" Harley big twin has a space of 2.975" between intake ports. These bronze Panifolds are a special edition and will be produced in very small numbers. 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 (knucklehead or '48 to '54 Panhead) you can buy a steel adapter nipple kit made by Colony sold on this web store to convert your 1940 - 1954 Bigtwin heads to o-ring style . This will covert your early plumber style heads to o-ring style that has a much more reliable seal. This product is 100% American made!!