Greetings, I was there for that race. Although some details are gone most remain. The car Denis was driving was a new car with a pinto body (I think). What happened was that someone blew a motor going into turn 1 which stacked up traffic with spinning cars and drivers checking up. The throttle stuck on the car Denis was driving. He hit the cars in front of him launching him airborne into the concrete wall in turn 1.One driver he went over was Leo Cleary who told me that it sounded like a jet going overhead. Denis hit so hard that he broke the new harness and hit his head breaking his helmet. He never drove after that . That I know of. Hope this helps answer your question. J