Harmonic Balancer Bolt, 12-Point Black Oxide fits Ford 351 Cleveland & Holden 253-304-308 5/8-18 Thread x 1.800" UHL, 5/8" Socket

As The Crankshaft Flexes And Twists, The Balancer Absorbs Incredible Amounts Of Kinetic Energy. To Ensure That The Balancer Is Locked In Position Arp Has Developed These Ultra Strong 200,000 Psi Bolts That Let You Exert Maximum Clamping Force. Special Features Include 1/4 Thick, Wide Area Washer And An Extra Tall 12-point Head That Accepts A Deep Socket And Aliminates The Worry Of Stripping The Head.