Stainless Steel headers Small Block Chevy for SBC GM Twin Turbo 305 350 400 Small Block Chevy SBC GM Twin Turbo 350 305 400 (Fit on 3RD Generation Camaro, Trans Am, Firebird, Chevelle, Nova TA SS Z28 383 with Manifold T3) Material: T304 Stainless Steel Inlet/Outlet: 1.75"/2.50" 2x Utilizes Factory O2 Sensor Position, O2 Sensor bung is welded on tubing so stock O2 sensor can be plugged in