I'm sure major loads of power and torque do amazing things to all the engine components. In my experience I have seen #3 caps broken in engine that drove into our shop. I've seen higher HP engine that, when taken apart, showed the signs of "cap walk". That "cap walk" is when the cap hops up and down as the engine load tries to plant the crank in the asphalt. The engine girdle keeps the crank in place. I'm NOT saying the crank doesn't twist, but I believe the flex of the crank during the "cap walk" is a wider/more common cause of failure. Reason?! From the engine work we have done over the last 14-15 years building Turbo Buick engine we have seen many cases of "cap walk" [mostly in the past few years, as more power is produced with stock components] than crank twist. If you read between the line of what Mike and I are saying.... We, you, us, are making more power than the stock components can handle.... .... it's time to upgrade.
Hope this helps.