These Header reducers are designed specifically for use with Hedman's 68140 series mid-length headers for swapping an LS engine into a 1968-72 GM A-Body car (Chevelle, EL Camino, GTO, etc). The 45° angle of these reducers make connecting the headers to your vehicle's 3” exhaust system easier. Uncoated mild steel construction, and sold in pairs. Included with 68140, 68143 and 68146 headers.