SPEED SECRETS: Great secret to engine power, torque not horsepower,.. rod length critical for two reason, leverage and combustion duration during the power stroke. 1st secret is balance & eliminate 1st & 2nd degree resonances, next thermal efficiency, heat is energy. 3rd secret, pent roof 4 valves best flow, low inertia valve train, 4th high compression 12:1 or more, 5th weight reduction. 6th high rpm is free power. Electric motors have 99% efficiency -v- engines at 25%.