About ChadS's new math

or Force equals mass times acceleration.

So if you lighten the pistons...all else remaining equal...the force at the crankshaft is less. BUT...since the lighter pistons DO have less mass, they accelerate faster from the same combustion force. So the result at the crankshaft is going to be the same, whether the pistons are heavier or lighter.

BUT...since lighter pistons accelerate quicker, they also DEcelerate quicker, as the lower piston weight carries less intertia [from Newton's first law of motion]. So a heavier piston might just carry an advantage in an RPM-limited class when coming to the end of a pull, although I'm not sure whether such an advantage might be measured in feet or rather in mere inches.