Hays SFI Approved heavy-duty flexplates for BBC 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 4mm thick center plate utilized on a Hays flexplate handles the brute force. These flexplates are supplied with a precision double welded ring gear and feature multiple engine and transmission bolt patterns. All Hays flexplates are zinc-dichromate plated to resist corrosion and are SFI certified under specification 29.1.