Manley Manly Witrid Int 66-84 Bt 99010N-2 Designed to out-flow and out-perform all others, even in the most severe environments One-piece forgings manufactured from high-temperature materials Feature swirl-polished, performance-oriented shapes and durable chrome-plated stems Up to 30% weight reduction over stock ensures a stable valve train, even at high rpm Available with a choice of stem protection: durable hard-chrome plating or state-of-the-art black nitride