Mike, the sprag is the weakest part in that transmission. It doesn't take much to pop that thing. When I did my burnouts at the race track, I always used a manual valve body, started the burn out in 2nd gear, then went to 3rd as soon as I could. Out of the water, I always stayed spinning for a short time then slowly applied the brake as I was letting off of the gas. NO FREEWHEELING ALLOWED. After 10 years of racing, I only lost a sprag twice. Once, when I was new and didn't know the correct way to do a burnout in a 727, the 2nd time when I broke a ring and pinion. I bet when you were testing your carbs and spinning the tires, you let the tires free-wheel while you were winging the throttle. Learn to do a proper burnout, whether showing off or getting ready to race at a track and you'll never lose another sprag. You have to shock the sprag the least amout possible when it grabs.
Like the racing manual says; Anytime a driveline component breaks; Axle, rearend, driveshaft, etc, the rear sprag has to be checked or the tranny can blow up.
Rob
