The JEGS 555-20912 Shaft Mount Rocker Arms feature upgraded trunnions, allowing for the use of a more aggressive camshaft. This design reduces deflection of the entire system by tying all eight rocker arms together on a single shaft, thereby improving valve train stability. The rocker pad remains centered on the valve tip, reducing wear on both components and eliminating valve train deflection. Note stock valve covers will clear with these rocker arms.