Race Master Exhaust ValvesSmall Block Chevy1.600'' Diameter5/16'' (0.3110'') Stem Diameter5.140'' Overall Length ( .200)Stainless Steel8/pkg. These 5/16'' (.3110'') stem valves are ONLY available with Bead Loc keeper grooves. Bead Loc valve locks are REQUIRED.Type: Exhaust Valve XH-426 MaterialHead Diameter: 1.600''Stem Diameter: 5/16'' / 0.3110''Installed Height: .200'' LongerOverall Length: 5.140''Tip Length: 0.290''Underhead Angle / Radius: 15° x 1/2''Margin: 0.080''Seat Width: 0.100''Top of Head: 9° DishWeight / Grams: 95