Proform Cam Lock Header Bolts 16Pcs .75"Uhl X 3/8-16" Thread 66752
(Prior to Dispatch)
Fits: GMBB 396-502 exc 348 & 409 Ford5.0L, SB 289-302-351W, Mopar413
Each PROFORM Grade 8Header Bolt is permanentlyassembled with a pair ofspecial washers. When the boltis torqued to 28+ ft-lbs, thewashers super-hardenedexternal teeth bite into andgrip the bottom of the bolthead and the top surface ofthe header. After beingself-locked in this manner,any bolt-loosening rotation isblocked by a wedge-lockingaction created by thewashers interfacing,matching cams. Its anuphill climb: vibration thatmight ordinarily loosen thebolt actually increases thewedge-locking tension,securing the bolt even more.Because this simplewedge-locking method usestension instead of friction,contact with oil actuallyfacilitates the wedge effect.When changing headers, PROFORMHeader Bolts can beuntightened with a normalwrench, lubricated, andreused.