This listing is for an Automatic transmission 153-tooth flexplate and bolts bundle compatible with 1968-1985 Chevy small block 305 327 350 and Chevy big block 396 402 427 all with 153 Tooth flywheel. Flexplate specifications are as follows: Outside Diameter 12.85 inch, Teeth: 153, Balance: Internal / Neutral (without weight), Pitch: 12-14, Center Hole diameter: 2.49, Torque converter 9.75 inch diameter, Safety Rating: OE-replacement (not SFI-approved).