Timmer, you're just a little confused on the stroke thing. Long strokes build more torque at a lower RPM, a matter of more leverage on the crankshaft. A short-stroke engine winds up to higher RPM, producing more horseopwer in the high-RPM ranges. The final drive gear ratio needs to match the stroke, higher gear ratios for long strokes, to utilize the extra torque, and lower gears, with higher RPM for the short strokes.

Horsepower=torque X RPM, divided by 5,250. There are a few fudge factors for temperature, humidity, and atmospheric pressure, plus a "volumetric efficiency" calculation, so raw figures don't always tell the whole story. I've got a computer program called "Desktop Dyno" that can predict HP and torque pretty accurately with the right info plugged into the formulas.
Jerry

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