In round numbers the crank spins and pistons go up/down 100+ times a second.(@ avg. 6200RPM) Through a run it spins 1000+ and gets shock loaded (gear changes) @ every200+ revs on average. I could see damage occurring at the metallurgy/molecular level and lasting awhile but actual physical damage would only go a short time (the 3 runs that day?) unnoticed before becoming catastrophic. IMO.
Also getting back to the "harmonics". The 2-7 pistons are next to each other in the firing order but are on complete opposites sides of the crank in the physical end of the equation. Crank is a fulcrum, hit it hard on one end the other is going to have a reaction. Don't know, just a thought.
In reality we're just batting around ideas which is interesting and what this forum/thread is all about. If you just had the 'get'r done' mentality you could/would just build it bigger better forge it and be done. But then it would never really be figured out which is the interesting part in, again MO.
And there would be no forum at all. LOL.