Hooker's RacingHeart Big Block Chevy Downswept, 3-Step Dragster Headers feature 2.125 inch/2.25 inch/2.375 inch stepped primary tubes to maximize exhaust flow, resulting in horsepower and torque gains over a broad rpm range. The 4.5 inch merge collector with merge spear design improves the transition of the exhaust pulse from the primary tube to the collector and maximizes the scavenging effect on the exhaust pulse. This helps maintain the velocity of the pulses as they travel through the collector. These headers are ideal for big block Chevy engines making over 1000 horsepower. They are available in both Chrome plated Mild Steel and Polished 304 Stainless Steel.