Proform Cam Lock Header Bolts 12Pcs 1"Uhl X 3/8-16" Thread 66753
(Prior to Dispatch)
Fits: GMV6, SB 265-400, Buick, Olds,Pontiac '79 & earlier Mopar BB383-440 exc 413, AMC V8's w3/8" bolts
Each PROFORMGrade 8 Header Bolt ispermanently assembled with apair of special washers. Whenthe bolt is torqued to 28+ft-lbs, the washerssuper-hardened external teethbite into and grip the bottomof the bolt head and the topsurface of the header. Afterbeing self-locked in thismanner, any bolt-looseningrotation is blocked by awedge-locking action createdby the washers 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.