Sounds like he is lucky to keep it in the car and straight? Heat....could be but I know the SS/AA or now called SS/AH cars (due to re-classifying these cars because of the Bow Tie Whiners).......run that e.t. and quicker, could not keep 8-3/4's in their cars back in the day and some of those cars used to use 12 bolt Chevrolet rear ends because they were the lightest but bent also, a lot of them are using dana's even though they are heaviest and some are to this day, using braced 9" housings.