All Pro Series Head Bolts are cold-forged to ensure molecular integrity, heat-treated prior to thread rolling and machining, and are rated nominally at 190,000 psi. ARP® Pro Series head bolt kits are application specific—designed for use with typically competition only components. These fasteners deliver superior strength and meet the ARP® “ZERO defect—ZERO failure” quality standard. Hardened and parallel-ground washers are included with each kit to ensure even load distribution and accurate torque readings. All Pro Series head bolts have a reduced wrenching 12-point head and wide area flange to eliminate the need for valve train removal for cylinder head retorquing and permits the use of larger diameter valve springs. Most applications have undercut short bolts that can help eliminate head gasket failures through providing more “stretch” to compensate for the additional compression of gaskets.

If you have a blown head gasket and are reworking the head and using a new metal head gasket, then it is critical to use ARP hardware. ARP builds very high tensile strength fittings and hardware used in race and performance cars all over the world. They are important in that they do not stretch like the factory bolts and studs and can be torqued down to 75 ft.lbs which is needed to help secure your head for higher boosted applications.