GM 602 & 604 Crate Intake Replacement Valves Sodium Filled Stems Valve Head Diameter (in): 2.000 in. Valve Head Diameter (mm): 50.800mm Undercut Stem: Yes Swirl-Polished: Yes Overall Valve Length (in): 4.911 in. Overall Valve Length (mm): 124.739mm Valve Stem Diameter (in): 0.344 in. Valve Stem Diameter (mm): 8.74mm Valve Material: Stainless steel Lock Groove Quantity: 1-groove Lock Groove Style: Conventional Quantity: Sold individually. Notes: Replacement valve for GM Performance CT350, Fast Burn 383, ZZ383 and LT4 engines and cylinder heads