11/32" Steel & Viton Valve Stem Seals (Suits: 0.530" Guides) These headers are designed with

These headers are designed with 5/16 in

or another that's set up the same

these U-joint girdles have a unique design that provides more bearing surface for the universal joint bearing cap

This makes them far superior to standard OEM fasteners in terms of durability

11/32" Steel & Viton Valve Stem Seals (Suits: 0.530" Guides) These headers are designed withValve 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.