WOW! Destruction

That could have been really bad.
I blew a clutch in my 65 Coronet, it broke the input shaft on the trans and shattered the stock bellhousing.

That pressure plate was slipping and it is really clear that the bolts came loose.
I suggest not re-using the flywheel, it has to be heat cracked from the disk slipping and the threads cannot be any good at this point.