Large diameter valves are essential for improved air flow. Cosworth high performance intake valves are produced from high quality stainless steel for maximum durability. Exhaust valves are machined from Inconel for high temperature (2400° F) reliability. Each valve features a swirl polished back for improved air flow and dished face for additional weight reduction. Some Cosworth High Performance Valves are only compatible with Cosworth Ultra Race Valve Spring Kits. Please confirm application before ordering.