This item is designed to fit specific vehicles. Please ensure correct part fitment before purchasing this project. Contact the seller directly for additional product information and availability.Precision machined flanges ; 5/16" thick ; Supplied with our premium head gaskets ; A wide variety of tube diameters and port shapes are available ;. Patriot Exhaust H7892 Chevrolet LS1-LS6 1 5/8"- 1 3/4" Round Port Header Flanges.Patriot Exhaust's machined header flange kits are available for many popular engine families. Header flange kits include gaskets and header bolts in most applications. Manufactured from 5/16" thick material.Exhaust Flange.Exhaust Flange.