340 Block Cost

where is the 340 thicker and stronger?

If so, at what power levels will that be significant?

My understanding was the 0.020” increased bore radius slightly un-shrouds the valves more for slightly increased head flow. I’d think this may be pretty minor on street engine with 2.02 valves.
Who said it was? I did not. I said it is "arguable" that it's stronger.