Need Help With Flywheel Thread

Most recent was a 56 chevy with a stock cast iron wheel, at irwindale, about a year ago. No scattershield, i guess teck didnt think it was fast enough to need one, and he was on street tires.
Slipping the clutch to get it off the line, after several passes it came apart on the third gear shift. It took out the stock steel tunnel, went thru the dash and destroyed it, busted the windshield, and pieces went thru the roof, and the passenger door.... and the drivers foot.
He was lucky to have an ankle that wasnt busted, or a foot gone.