For SBC Chevy Hugger Headers Shorty Stainless Steel 265 283 305 350 383 400 GM Fit for 1966 --1996 SBC 265,283, 305, 307, 327, 350 & 400 engines. These are "block hugger" type shorty headers which allows for increased clearance while still providing excellent flow. Made with 1 5/8" OD diameter heavy duty mandrel bent 18 gauge tubing Large 2 1/2" collectors. Reducers are 2 " 4 1/4" length from the bottom edge of the head to the outside of the middle tubes