ARP 4306802 Stainless Steel 3-Piece Lower Water Pump Pulley Bolt Kit Provides the reliability you need for racing or high performance street applications Manufactured from rust-proof stainless steel with compact 12-point style heads Rated at 170,000 psi, which is stronger than Grade 8 hardware Features a 5/16-24 thread size, 2.125 under head length, and 1/2 socket size Kits come complete with washers