For SBC 55-57 Chevy Ceramic Coated Headers 265 283 302 305 327 350 383 400 Fits for 1955-1957 small block Chevy V8s engines using standard exhaust patterns such as 265 283, 302, 305, 327, 350, 383, 400, etc. Made with 1 5/8" OD diameter heavy duty tubing. Thick 5/16" flanges to resist warpage!Works with both straight and angle plug heads. The "3/4 length" design provides more ground clearance than full length headers, and makes more power than "shorty" style headers. Fits standard and Vortec-style small-block Chevy heads (not D-port, LT-1 or ZZ-4