Constructed of thicker than stock steel plate to withstand the stress of high stall speed converters and high RPM engine Securely welded ring gear with dual bolt pattern for use with either Powerglide or Turbo-Hydromatic transmission Meets SFI specification 29.1 for racing Hays heavy-duty flexplates for high performance and competition engines are constructed of a thicker than stock steel plate, enabling them to withstand the stress of high-stall torque converters and high-RPM engines. While factory stock plates tend to crack around the crankshaft hub when punished under high torque and RPM conditions, the thicker Hays flexplate handles the force. These H.D. flexplates are supplied with a ring gear that is securely welded in place and feature dual bolt patterns for use with either a Powerglide or Turbo-Hydromatic torque converter. All Hays heavy-duty flexplates are zinc-dichromate plated to resist corrosion and are SFI certified under specification 29.1.