Proform self-locking wedge header bolts get a grip on your headers that won't let go—until you're ready! These permanently assembled bolt sets feature special washers with super-hardened serrated teeth that, when torqued to 28 lbs.-ft., bite into and grab the bottom of the bolt head and the top surface of the header. Any bolt-loosening rotation is blocked by the wedge-locking action created by the washers' interfacing cams; but what's really impressive is that engine vibration—the enemy—increases the tension, making them even more secure! The bolts are re-useable and you can count on them to not fail. Proform self-locking wedge header bolts put an end to the constant tightening for a leak-free, headache-free future. They're available in different finishes and sizes for applications from 1965 and up.