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.