Mr.Gasket Headlock Locking Header Bolts are designed to make header installation very simple using 2-in-1 self-locking bolts that eliminate the need for lock washers. These innovative bolts have 24 equally spaced serrations in the face of the hex head designed for performance engine builders. The bolts grab and lock onto your manifold surface, virtually eliminating the chance that one might back out from vibration. Mr.Gasket Headlock locking header bolts are available for many domestic applications, including Chevrolet, Chrysler, Ford, AMC, Oldsmobile, and Pontiac. Manufactured from stainless steel they are designed to withstand tensile strengths of 150,000 pounds per square inch and are offered with a bright polished finish.