1-9/16 inch width x 1-25/32 inch height Oval Intake Ports; Ford L6 300 '65-'86 | Combination Intake/Exhaust with Riser Gasket| Manifold or Headers| 2 Piece Set 1-11/32 inch width x 1-3/4 inch height Square Exhaust Ports Includes riser gasket 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