Thick, flat washers go under the bolt head for security and bolt tension. Use Permatex's The Right Stuff between the bolt head, washer, and block to prevent oil leaks. Cross bolts are torqued first to 20 ft-lbs, then, 40 for final torque. Bolts must be torqued in a specific crisscross pattern beginning at the front two, then the back two, then the center. Main cap bolts have to be torqued first to 95-105 ft-lbs. Fasteners can be sourced from ARP or AMK Products.