Remflex 2030 Exhaust Gasket for Chevy V8 Engine, (Set of 2) 2 inch width x 1-7/8 inch height Irregular Shape Stock Sport; Chevy V8 - GMC BB 454/496/502 Gen. Mark (IV,V,VI),('91 and Newer), Manifold or Headers, 2/Set For use with stock cast iron and GM Performance aluminum cylinder heads There are no rubber binders or composite materials in Remflex exhaust gaskets so they will not shrink or harden due to time or temperature eliminating the need to go back and continually retighten your flange bolts Heating and cooling of the exhaust system causes header and manifold flanges to warp resulting in gaps between the head and header which Remflex exhaust gaskets seal completely due to the thickness and compressibility of the 100 percent flexible graphite