Edelbrock part #7203 Intake Gaskets for 1965-1990 & later Mark IV, Oval port 396-402-454 Big-Block Chevy allow for optimum flow and performance. Any gasket can create a seal, but a good gasket can do it with less clamping force, and for a longer period of time. The new MP-2N Micropore technology does not use solvents making our gaskets environmentally friendly. Impervious to most chemicals, this synthetic fiber composite provides a high recovery under load. This means that when compressed, the gasket will conform to any imperfections on the sealing surface even using lower flange pressures. A nitrile bead around each port opening makes the seal even better.