Nobody is going to break a big bar. The ones that break are the small bars. A heavy B body will almost break the race bars just sitting still. The tiny bars have to be twisted a lot just to support the weight of the car. A big bar only has to be twisted a small amount to support the same weight.

Big bars aren't used for drag racing since they kill the weight transfer and they put extra weight on the nose of the car. Small bars work great for drag racing but the high level of stress kills them fairly quickly.