For Chevy Small Block V8 High Performance 4-1 Design 2-PC Stainless Steel Long Tube Exhaust Header Kit Made of high quality steel with 2 x 4-1 direct bolt-on design TIG welded CNC machine flange Metal gasket included / Inlet: 1.75"x1.5" (Oval) / Outlet: 2.875" Increase high flow air, instantly gain 10 to 15 Hp. / Tq Application: Please check part finder on top of the page (Professional Installer is Highly Recommended) (No Instruction Included)