Remflex 2031 Exhaust Gasket for Chevy V8 Engine, (Set of 2) 1-7/16" Round Port; Chevy V8 -Small Block 262 - 400, 1-7/16" Round Port, For Raised Weld Bead Headers, 2/Set Exact Match to Hedman Header Pattern For use with raised weld bead headers; additional sealing material is provided around the weld bead to provide a better seal 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 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