(8) Eight Premium 1-Piece Stainless Steel Plasma Nitrided Intake Valves -. Notes: 1 Groove. Undercut Valve Stems, Swirl polished underheads. Nitrided Stems and Top. They are forged from the highest grade stainless (21-4N) steel, plus they are plasma nitrided on the stem and top of the valve.
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