These Severe Duty Gen II custom valves with unmatched strength and superiority are the only valves of their kind. Exhaust material XH-428 and intake material NK-844 are paired together for ultimate dominance over all others. With four times the tensile strength of competitors' intake valves and supremely better fatigue life, Manley Severe Duty Gen II custom valves truly show their commitment to seeing that you're there at the finish. You decide the head diameter and seat and margin widths, as well as valve length, groove type, and location for the perfect custom setup!

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