Caprices really aren't known for their frame or trunk strength, unless they have the factory-installed trailer towing option. The above result has been a common occurrence on every Caprice I've run.

The derby officials will often help me fix this problem with one of the front-end loaders they use to smooth the pit between heats. I attach a chain to the bottom of the "trunk", and then the loader picks up the back of the car and shakes it violently while in mid-air to bend the rear-end back to normal. (Yes, that's me leaning against the car.) See the Photo Gallery for this and other pictures.