Severe Duty Intake ValvesSmall Block Chevy2.020'' Diameter5/16'' (0.3110'') Stem Diameter5.010'' Overall Length (+.100)Stainless Steel8/pkg. Installation Note: These 5/16'' (.311'') stem valves are ONLY available with Bead Loc keeper grooves. Bead Loc valve locks are REQUIRED.Type: Intake Valve NK-844 MaterialHead Diameter: 2.020''Stem Diameter: 5/16'' / 0.3110''Installed Height: .100'' LongerOverall Length: 5.010''Tip Length: 0.290''Underhead Angle / Radius: 12° x 3/8''Margin: 0.050''Seat Width: 0.080''Top of Head: 7° DishWeight / Grams: 108