Remflex 2006 Exhaust Gasket for Chevy V8 Engine, (Set of 2) 1-3/8 inch width x 1-1/2 inch width Square Port - Matches the Stock cast iron Head Port; Chevy V8 - SB 262, 265, 267, 283, 302, 305, 307, 327, 350, 400, Stock Port, Manifold or Headers, 2/Set Port configuration comparable to Fel-Pro 1404 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