For Chevy 6 Cylinder/CYL Stainless Steel Exhaust Header - 216 235 261 Made of high quality steel with 2-pieces 2-1 direct bolt-on design TIG welded CNC machine flange Metal gasket included / Inlet: 2"x1.65" (Rectangle) and 1.65" (Square) / Outlet: 2" 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)