B&M 20237 SFI Approved Performance Flexplate Upgraded flexplate for high RPM (6000+) and performance applications, ranging from street to extreme duty racing SFI spec 29.1 approved, NHRA and IHRA legal for all classes Single bolt pattern design features 10-3/4" bolt circle; starter ring gear tooth count is 153 For internally balanced setups Backed by the manufacturer with a 1 year limited warranty