Beginning June 1, 2017, 2.9L Whipple supercharger rotors used in the Stock and Super Stock categories can be no more than 268 millimeters (10.550 inches) in length and no larger in diameter than 104.4 millimeters (4.110 inches). The NHRA Technical Department will periodically confiscate and inspect these superchargers to insure compliance with this policy. Anyone found to have a larger supercharger rotor or to be modifying any part of the supercharger to improve performance will be subject to at a minimum disqualification from the event. If additional penalties are warranted, they will be determined by NHRA in its sole and absolute discretion. If you are unsure of the size of your supercharger rotor, please contact Whipple Superchargers for confirmation.    

Glen Gray

NHRA

Vice President Technical Operations