The bore and stroke specs will make a factor in the engines characteristics. The OS uses an over square engine design. Thats an engine that has a larger bore than stroke. This favors a fast revving engine with higher RPM capability. The italian mills use under square design, the bore is smaller than the stroke. This favors higher torque, but will rev a bit slower and not have as much high RPM. With this said, one factor you don't see is the rod length. This will also change the engines characteristics. If two engines have the same bore and stroke with everything being identical except for differnent rod lengths, they will differ in the power band area. Both might produce the same power, but the longer rod engine will have a torque at a higher RPM, while the shorter rod engine will have a fatter torgue band and it will be lower value. If you lengthen the rod on a long stroke, you will move the power band up. This has been done before. If you install a longer rod and shim the bottom of the sleeve the same to compensate, you will make the engine have power in the higher RPM range. Also, take into account, that the big bore short stroke design works with a hot plug (advanced spark timng) while a longe stroke uses a medium plug ( less advanced timing). This is due to piston dwell timing. The long stroke engine has the piston hanging at TDC and BDC for more crank degrees than a short stroke engine. If I've lost you guys by now, go over this engine article so it explains this a bit more, at least the rod ratio part.

http://www.e30m3performance.com/tech...atio/index.htm