This kit is specifically engineered to reduce rocker arm clatter and oil leaks from the rocker shaft end plugs Contains heat treated pre-loaded spacers and seals to rebuild all four rocker shafts on Shovelheads with either solid or hydraulic lifters By design, this kit holds the pushrod end of the rocker arm in constant adjustment with the use of a pre-loaded spring spacer Kit eliminates the guesswork of rocker shaft shims and provides a clatter free arm assembly, regardless of how hot the engine is run Also included are four Rocker Seals which will completely seal the rocker shaft end plugs against leaks. These seals are designed to form-fit the shaft hole in the rocker box for a perfect leakproof installation