8mm LS Steel & Viton Dual/Single Spring Valve Stem Seals (Suits: 0.500" Guides) this nut is an essential

this nut is an essential part of maintaining the tension and alignment of the supercharger belt

and 3/8 in

capable of withstanding valve spring load

Complete kit with Multi-Layer Steel (MLS) Head Gaskets

8mm LS Steel & Viton Dual/Single Spring Valve Stem Seals (Suits: 0.500" Guides) this nut is an essentialValve stem seals control the lubrication of the valve stem as it slides in the valve guide. Too little oil causes stem and guide wear. Too much oil increases oil consumption and can cause a buildup of carbon, leading to valve seat damage and early valve grind. Speedmaster valve seals are posi stop seals made from high temperature Viton material for a long lasting seal.