REALLY? BROKEN FLYWHEEL?

I had a flywheel crack in a 73 formula 400 Firebird at around 88K miles. No work had been done prior. I bought it at 50 some K miles. Don't know how the previous owner drove it.
Maybe your new TQ pushed on this flywheel a little bit differently but mechanical/metal things do just break with no reason other than stress over time. I've seen crank shafts broken diagonally through a bearing surface, firewall cracked at the clutch master cylinder, a tiny crack in a brake caliper, and those just the first few examples I recall.
At a quarter million miles, I think you got your moneys worth out of that flywheel.