ARP 2342501 Harmonic Balancer Bolt Kit For Select Chevrolet Small Block Applications Ensures that the balancer is locked in position as the crankshaft flexes and twists Rated at 200,000 PSI, which is considerably stronger than Grade 8 hardware Compact and extra tall 12-point head eliminates the worry of stripping the head by accepting a deep socket Features an under head length of 2.470, diameter/thread size of 7/16 -20, and a socket size of 13/16" Includes a wide area washer that is 1/4" thick