Not as far as I know.
What I have read is a certain famous racer switched his 727 to a 904 with winning success up until the others complained and was promptly banned from racing until he dragged the officials down to the local dealer where a car was put up on a lift as to prove it came stock with the car and this legal for competition.
I believe those were Canadian cars that were shipped with the 904 but NHRA was not aware of it. Thus the 727 pro trans with 904 internals was allowed. Correct me if I have this wrong.
