Our ARP torque converter to flexplate bolt kits are the strongest bolts you can get to attach your torque converter to flexplate for high horsepower and/or highly stressed applications. Made from 200,000 PSI forged aerospace alloy, these were originally developed for NASCAR winston cup competition. The bolts are fully heat treated prior to thread rolling and machining. Finished in black oxide for good looks and corrosion resistance. Flat 12pt head design ensures no clearance problems during installation. If you have a stroker engine with aftermarket components, high stall converter, etc... these are must have item. You simply can not put in stronger bolts than these. These are the smaller 5/16" bolts used for most stock type torque converters. For most performance torque converters, use our 7/16" bolt kit instead, which is part # 129-1052.