I am not sure why the oem is not suitable, I did not say it was'nt suitable in my simple and single question....so I don't know why you are surprised all of a sudden.

I think the subject of failed harmonic dampers on the 617 has its own chapter on this site and I see yet another person in line for some help on the subject. It seemed like a fair question, that may help others, or bring about some further insight to the subject.

I could never figure out why the round dowels when a simple square keyway works for less complicated machinery like sbc.
I guess that brings the question as to why is there an aftermarket for harmonic balancers in the first place, when oem is so suitable.
If there was ever a canidate for a different design for this problem then I could forsee one for this.
There is nothing worse than pouring money into something and find the damper spinning material off the cranksnout rendering an otherwise perfect running engine useless.
Could just get a different motor and hold my breath that it does'nt happen with the next one. Seems to be a trend according to this site and others. I guess having 800 000 miles on yours you did not run into this problem so we can write off age or mileage as the culprit. Oh and with mileage goes the vibration reason.
OR...Maybe you have had this problem, hence a solution you could share.
I guess I have trouble with not knowing why this happens. As far as I know nobody has offered a reason.
Can't be the tons of horsepower it is putting out.
Share your wares on why the wear. I am curious now why the oem is so great.