MRG Torque Converter to Flex Plate Bolts are forged from high quality steel and heat-treated for extra strength, these Grade 8 fasteners are a must for all hi-performance applications. Black plated finish helps resist rust and corrosion. Kits are complete with lock washers, where needed. Application: GM TH350 & Powerglide, 3/8″-24 x 5/8″ (w/nuts) 3