Wilson Manifolds carburetor base gaskets are made of a premium race proven paper type material. They are a result of our extensive research and development programs with our customers in applications from dirt track racing to NHRA Pro Stock racing. All of our gaskets are precision cut to fit our Wilson Manifolds light weight spacer shape so that there is no obstruction to flow through the carburetor and/or spacer and no trimming required. Also includes holes for Wilson Manifolds locating dowel pins for precise alignment of the gasket.includes holes for Wilson Manifolds locating dowel pins for precise alignment of the gasket. Our rubberized washers must also be used in conjunction with the rubber gaskets to achieve full isolation of the carburetor.