IIRC, You'd need roughly 8000-8500 rpm input shaft speed to hit the 904 critical mass RPM point. Yeah, there are a lot of those mopars spinning that level running around!
Even with the shifter in second on a auto VB, you are still in low gear. If you have that situation, as soon as it's up on the tire, get to second gear. I used to get the tire turning with less than full throttle and click to second and lay into the pedal, click to 3rd and let it begin to roll out. If you mash the gas right out the gate in low gear, that's when bad things may occur when something breaks.
With a manual VB, absolutely, start in second with a 727.
Blankets might slow things down. I've seen blankets shredded and shrapnel all over the place inside a car from a 727 bomb going off. Sometimes you are lucky, other times you aren't.