Each PROFORM Class 12.9 (equiv. Grade 8) Header Bolt is permanently assembled with a pair of special wedge-locking washers. When the bolt is torqued to 28+ ft.-lb., the washers’ super-hardened external teeth bite into and grip the bottom of the bolt head and the top surface of the header. After being self-locked in this manner, any bolt-loosening rotation is blocked by a wedge-locking action created by the washers’ interfacing, matching cams. It’s an uphill climb: vibration that might ordinarily loosen the bolt actually increases the wedge-locking tension, securing the bolt even more. Because this design uses tension instead of friction, contact with oil actually facilitates the wedge-locking effect. When it comes time to change headers, PROFORM Header Bolts can be loosened with a normal wrench, lubricated, and reused.
- 0.984″ x 8 mm, 12 bolts (66754)
- 1.181″ x 8 mm, 12 bolts (66755)
- 1″ x 3/8″, 16 bolts (66756)
- 3/4″ x 3/8″, 16 bolts (66752)
- 3/4″ x 3/8″, 12 bolts (66751)
- 1″ x 3/8″, 12 bolts (66753)
Though this is not a paid review, this content has been produced by The AAM Group™ in support of manufacturers with whom it has a business relationship.