Proform's grade 8 Wedge-Locking header bolts are designed to prevent backing out by using a pair of special washers that are permanently attached.
How do they work?
When torqued to 28+ ft.-lbs, the super-hardened external teeth of the washers grip the bottom of the bolt head and the top surface of the header.
After being self-locked in this manner, any rotation that might loosen the bolt is blocked by a wedge-locking action created by the matching cams of the washers.
It's an uphill climb: vibration that might ordinarily loosen the bolt actually increases the tension of the wedge-locking, securing the bolt even more.
Because this simple method uses tension instead of friction, contact with oil actually facilitates the wedge effect.
When changing headers, PROFORM Header Bolts can be untightened with a normal wrench, lubricated, and reused.
These bolts are sold in complete sets, enough for both headers.
