340 or 408?

500 hp out of a 414/416/408 is a lot easier, and probably a lot easier to live with, than a 500 hp 340.
The extra stroke doesn't mean it can't rev as high as a 340 stroke, it just means the power might drop off a little sooner, and you won't NEED to rev it as high.
Imo, revability is determined by head flow, and valvetrain, not stroke length.