Stage 8 (8900B) 8mm x 30mm Locking Header Bolt Kit for Chevy LS1/LS2/LS6 Engine Grade 8 bolts will not stretch when hot Duplex nickel finish for a superior look and corrosion resistance Double Hex Head includes 3/16 inch recessed Allen Head for easy installation Removable and reusable Can visually inspect - no need to put a wrench on to check tightness