I remember seeing one major structural failure at N.Y. National Speedway (1/4 mile track) back in the mid 1970s. Some guy was racing a mid-sixties 'vette. He cranked the revs and dumped the clutch on the "green." The front end had lifted with one side lifting higher and higher than the other - then CRACK! The body broke in half about mid way between the front and rear wheels. This happened on launch and he skidded to a stop within about 100 feet. I don't know if it is true or not, but somebody in the pits said that 'vettes had "x-frames" and that the owner had cut circles out of the frame to reduce weight, but, again, that was hearsay.
