340 Engine Shake

The crank can be polished, and many 60 over 340s are running around, I've built a few, including my own 69, I bought new, and wouldn't be numbers matching without 3 sleeves and going 60 over.
Cylinder wall pattern during misc teardowns show no distortion, which I have seen with weak cyl walls .
Ran 12.5 pistons racing at 60 over .
Same pistons trimmed 3 times over the years, about 10.5 now.
Hope it helps, cheers .