The closest I've gotten to this was when I was driving a 97 Sable with a bad head gasket, and the car kept idling really rough. Right before that was replaced, I parked in front of a fence. Even though the brake was down, the RPM shot up, and the car rammed its bumper straight ahead. I only bent the wooden fence a little bit, but I backed up the car, and nothing showed. I even told the owner about it, but he couldn't see anything was different.
Don't worry, though. We don't drive our cars with bad gaskets. So far, the Bonneville hasn't hit anything as long as I've had it. I have managed to keep the body only as trashed as the day I got it, but with a new fender, redone interior, and smoother paint.