Maybe it's too obvious to point out, but no one has yet mentioned that long stroke means that the lever arm length through which the crank twists the driveline is 1/2 the stroke, so an engine with 10% longer stroke, all other things being equal, will have a 10% higher torque rating. Dick Benjamin ----- Original Message ----- From: D. Dardalis <dardal@xxxxxxxxxxxxxxx> >All these real early engines > had a high stroke/bore ratio (more than 1.2, 1.3?). Also, they had a lot > of low end torque, by modern standards. >However, the very strong low end is NOT really a direct result of > the long stroke (although there is some relationship between the two that > becomes important in high compression engines, like diesels, won't get into > why). The low end torque of these old engines was more related to the very > small cams with almost zero overlap, tiny intake valves and ports (compared > to later engines), small carburetors and narrow intake manifolds.