These Hooker BlackHeart long tube headers are designed for the popular GM G-Body vehicles using a Small Block Chevrolet engine. These headers use 1 3/4- inch primary tubes, with square port flanges, that lead to a long transition 3.0-inch collector with a merge spear to increase exhaust pulse velocity. Constructed from light weight 18-gauge, mandrel bent, 304 stainless steel for maximum exhaust flow and durability. These headers include O2 sensor bungs that can be used for EFI applications or for air/fuel meters (plugs also included). Tube geometery is designed for maximum ground and tube clearance for a hassle-free installation. All hardware is included. These headers are designed to be used with Hooker BlackHeart's 70501364-RHKR exhaust system.