Professional Products Typhoon LS1/LS6 85mm Intake Polished.

This unique new design features a larger plenum volume than stock or aftermarket manifolds, somewhat similar to the 2006 ZO6 manifold.This larger volume is particularly suited to big inch engines but extensive dyno testing on a stock LS1 also shows substantial gains, especially in the mid-rpm ranges.Tested primarily against a leading aluminum aftermarket manifold that is similar in design to the LS6, the Professional Products intake showed equal power on the top end with an additional 12 to 15 hp in the 3,000 to 4,000 rpm range. It was also tested against a factory LS6 and produced an additional 17.7 hp at 6,200 rpm on an engine dyno.