The FF1600 flywheel bolts are subjected to some incredible stresses even when everything is working perfectly. Stock flywheel bolts are just barely up to the task and require frequent replacement. These super-strength bolts (originally developed for NASCAR Sprint Cup flywheel bolts) are rated to 200,000 psi tensile strength. Sold in sets of 6 bolts. These 3/8-24 x 0.900" bolts also fit BMC A-series engines.