Sorry I don't quite follow how the backing plate will prevent rotation in the event of the block bolts busting off seeing as the backing plate uses those very same bolts.
Again, a 1/8" aluminum backing plate adds near zero structural integrity.
I'm not arguing that the lakewood bell is not stronger than the QT, it is. However, if your running the kind of power to blow a modern flywheel then you should be using a Kevlar blanket.
Padded sun visors are specified on new cars to meet safety specs, but I think their about as helpful as those bottom bolts. Besides if you don't cut that bottom flange off the road will grind it off for you.
I think the moral of this story was "Don't use 40yr old, used, stock flywheels on your 800hp motor."
BTW quoted from the thread referenced:
Of course I should have used the SFI flywheel 90 miles away. If this one didn't blow the thread would have just been about the power we got.
I'm only trying to show why never to use a stock flywheel.
In our defense we weren't launching and shocking the flywheel. We were rolling into it at over 3000 rpm and cutting off at 6500.