PRW Platinum Series SFI-Approved Steel Flexplate Chevrolet Short Bed 1957-80. 153 tooth, .187 inch thick core and high integrity design with 90 degree V6 internal balance. These flexplates are engineered to handle extreme duty applications and designed to take the punishment of today's high horsepower engines. The 5 millimeter thick centerplate provides a solid foundation for these new designs. Ring gears are precision welded to meet SFI specifications, utilizing robotic machinery and cold-welding process.