ARP HEAD BOLT KIT TO SUIT HSV W427 VE LS7 7.0L V8ARP produces fasteners from a wide combination of materials going from famous hardened steel and 8740 chrome moly to exotic alloys that have been created to deal with space travel. 8740 chrome moly used in this head bolt kit is classified as a quench and temper steel, that can be heat treated to provide tensile strengths between 180,000 and 210,000 psi. This kit comes complete with hardened washers and high strength hex nuts. This head bolt kit suits