Bolt Kit for Flywheel Flexplate The factory flexplate bolts are torque-to-yield and need to be replaced whenever loosened. Increased torque output from the engine can lead to compromised flexplate bolts which can increase engine noise/vibration, and cause transmission problems. PPE Flexplate Bolts are constructed of premium chrome-moly alloy with over 215,000 psi yield strength and over 230,000 psi tensile strength, which help secure factory or aftermarket flexplates. These are the ideal flexplate bolts for engine rebuilds and performance builds. Features High performance chrome-moly alloy Verified 230,000+ psi tensile strength 12-point bolt head Black oxide finish