Skunk2s engineers looked to the popular 06-10 Civic Si’s RBC intake manifold for inspiration when developing our Pro Series Intake Manifold for K-series engines (excluding 06-10 Civic Si) and went back to the drawing board. Each of Skunk2’s Pro Series Intake Manifolds for Honda’s K-series engines feature larger plenums and shorter, oversized runners when compared to the RBC, and are cast with thicker wall material, leaving room for further porting for high-horsepower applications. Instead of producing a manifold with a significantly oversized plenum and excessively short runners that would sacrifice mid-range power, Pro Series manifolds were designed for the “street enthusiast” who wants more power but doesn’t want to sacrifice mid-range performance to get it. The results are improved airflow, an enhanced venturi effect, and both mid-range and top-end power gains. Skunk2’s all-new, cast-aluminum Pro Series Intake Manifolds for Honda’s K-series engines are a direct-fit replacement for all K-series engines (excluding 06-10 Civic Si) thanks to their unique, patent-pending water neck designs and throttle body flanges, which are compatible with OEM throttle bodies as well as those as large as 76mm. The special water neck designs eliminate the cutting that would otherwise be involved with some RBC applications and the supplied thermal-insulated intake manifold gasket makes for a truly bolt-on installation (no drilling or modifying required). Pro Series manifolds also incorporate an angled-runner design, which allows for ample hood clearance on ’88-’00 Civics and ’90-’01 Integras with K-series engine swaps, as well as additional core support clearance on ’02-’05 Civic Sis. Pro Series Intake Manifolds offer horsepower and torque gains greater than the popular RBC manifold but without compromising mid-range power output.