As long as the counterweights for a particular cylinder pair are the right position and size, the stroke length doesn't necessarily matter. CNC machining has opened up an entirely new bunch of possibilities for rule-benders to exploit. Back in the dark ages of dirt track racing, some guys would bore one cylinder bank of a flathead Ford V8 way oversize, and only pull the cylinder head over the "stock" bore half of the engine during an inspection. Those engines were fun to balance!
Jerry
