I ran my 360 that was in my Duster for 3 1/2 years before I tore it down to check everything and add some power. At 529Hp from my dyno, it looked great. No cap walk, nothing. It was hard blocked and I took care of it, but it was foot braked.
Added 30HP to the engine by upping compression .75, larger FT cam, and a 1000HP carb over my old 950. Foot braked it for a few passes then went transbrake/2 step. I put less than half as many passes on that engine as the first and upon teardown there was MASSIVE cap walk!
I was really surprised. I never mixed fuel, always ran VP110 fresh in the 5gal cans. I attributed the cap walk to the transbrake/2 step and having to launch such a heavy (3320lbs with me) car.
I've also seen a block from a 550HP bracket deal with a cracked main after 300+ runs. That's all I've seen personally so it looks like since I've seen very few failures that my not exist???? LOL!