Howards Cams Intake and Exhaust Valves increase the intake and exhaust flow of your engine. The increased intake and exhaust flow boost horsepower in naturally aspirated engines. Each of these valves is CNC machined from a solid piece of stainless steel. The valves are black nitride finished, providing a superior surface hardness and extended service life. The surface hardening also helps these valves run cooler in nitrous, turbo, and supercharged applications.