A tunnel ram manifold for the control of high velocity mixture flow, especially above 8500 rpm. Suited to drag race engines operating at 6500-10,000 rpm and race boat engines above 7000 rpm. Does not fit raised port cylinder heads or 1987 and later cast iron heads. Carburetor Recommendations: Use appropriate racing carburetors. Installation Notes: Distance from carburetor center to carburetor center: 8.88". Manifold top with bottom height: 9.25". H.E.I. ignition will not clear manifold. Recommended intake gasket: Fel-Pro #1206.