This Chrysler flexplate has a dual bolt pattern 10 in. and 11 1/8 in. and is SFI 29.1 approved(recertification required every 3 yrs.). Fits 1962 and newer Chrysler, Dodge, Plymouth Torqueflite A727 automatic transmissions. Bolts onto 6 bolt internally balanced crankshafts.NHRAIHRA legal for all classes and ideal for street applications to extreme duty racing and high RPM (use 6,000 and above). B&M's new Radial Tension Technology puts a new spin on flexplate technology. As engine performance levels increase, stronger flexplates become necessary. Until this point, stronger flexplates meant thicker flexplates. This works, but it adds unwanted weight and prohibited the flexplates from working as it was designed. Flexplates are designed to provide a protection against converter and transmission run out or OEM misalignment, which will cause transmission andor converter failure. A rigid flexplate gives no protection. The ultimate design for a flexplate is extreme strength, flexibility and minimal weight. B&M's new RTT performance flexplate accomplishes this goal. B&M's design allows for the removal of unnecessary material from non-critical stress areas. Less material means less weight giving you the benefits of a lightweight, flexible design with thicker material for maximum strength!