Brand: Airflow Research (AFR) Manufacturer's Part Number: 7631-1 Part Type: Valves Product Line: AFR Replacement Stainless Steel Valves Automotive Fittings Part Number: AFR-7631-1 Valve Position: Exhaust Exhaust Valve Head Diameter (in.): 1.880 in. Exhaust Valve Head Diameter (mm): 47.752mm Exhaust Valve Stem Diameter (in.): 0.344 in. Exhaust Valve Stem Diameter (mm): 8.74mm Exhaust Overall Valve Length (in.): 5.450 in. Exhaust Overall Valve Length (mm): 138.430mm Undercut Stem: Yes Swirl-Polished: Yes Valve Material: Stainless steel Lock Groove Quantity: 1-groove Lock Groove Style: Conventional Valve Head Style: Dished Quantity: Sold individually. Description: AFR replacement stainless steel valves are designed to fit your AFR cylinder heads without any modifications. They are made from stainless steel with chrome stems and hardened valve tips. AFR replacement stainless steel valves are also swirl-polished and fully machined. Both the materials used, and the heat-treating process are superior to the original equipment replacement pieces.