Found a cool site with a bunch of equations for solving for "stuff" orig posted on http://www.westernracing.com/reference/formulas.htm Automotive Formulas Formulas for displacement, bore and stroke: cylinder volume = pi/4 x bore^2 x stroke stroke = displacement / (pi/4 x bore^2 x number of cylinders) Formulas for compression ratio: (CylVolume + ChamberVolume) / ChamberVolume cylinder volume = pi/4 x bore^2 x stroke chamber volume = cylinder volume / compression ratio - 1.0 displacement ratio = cylinder volume / chamber volume amount to mill = (new disp. ratio - old disp. ratio / new disp. ratio x old disp. ratio) x stroke Formulas for piston speed: piston speed in fpm = stroke in inches x rpm / 6 rpm = piston speed in fpm x 6 / stroke in inches Formulas for brake horsepower: horsepower = rpm x torque / 5252 torque = 5252 x horsepower / rpm brake specific fuel consumption = fuel pounds per hour / brake horsepower bhp loss = elevation in feet / 1000 x 0.03 x bhp at sea level Formulas for indicated horsepower & torque: horsepower = mep x displcement x rpm / 792,00 torque = mep x displacement / 150.8 mep = hp x 792,000 / displacement x rpm mep = hp x 792,000 / displacement x rpm mechanical efficiency = brake output / indocated output x 100 friction output = indicated output - brake output taxable horsepower = bore2 x cylinders / 2.5 Formulas for air capacity & volumetric efficiency: theoretical cfm = rpm x displacement / 3456 volumetric efficiency = acutal cfm / theoretical cfm x 100 street carb cfm = rpm x displacement / 3456 x 0.85 racin carb cfm = rpm x displacement / 3456 x 1.1 Formulas for tire size & their effect: effective ratio = (old tire diameter / new tire diameter) x original ratio actual mph = (new tire diameter / old tire diameter) x actual mph Formulas for g force & weight transfer: drive wheel torque = flywheel torque x first gear x final drive x 0.85 wheel thrust = drive wheel torque / rolling radius g = wheel thrust / weight weight transfer = weight x cg height / wheelbase x g lateral acceleration = 1.227 x raduis / time^2 lateral weight transfer = weight x cg height / wheel track x g centrufugal force = weight x g Formulas for shift points: rpm after shift = ratio shift into / ratio shift from x rpm before shift drivehsaft torque = flywheel torque x transmission ratio Formula for instrument error: actual mph = 3600 / seconds per mile speedo error percent = difference between actual and indicated speed / actual speed x 100 indicated distance = odometer reading at finish - odometer reading at start odo error percent = difference between actual and indicated distances / actual distance x 100 Formulas for MPH RPM gears & tires: mph = (rpm x tire diameter) / (gear ratio x 336) rpm = (mph x gear ratio x 336) / tire daimeter gear ratio = (rpm x tire diameter) / (mph x 336) tire diameter = (mph x gear ratio x 336) / rpm Formulas for weight distribution: percent of weight on wheels = weight on wheels / overweight x 100 increased weight on wheels = [ distance of cg from wheels / wheelbase x weight ] + weight Formulas for center of gravity: cj location behind front wheels = rear wheel weights / overall weight x wheelbase cg location off-center to heavy side = track / 2 - [ weight on light side / overall weight ] x track cg height = [ level wheelbase x raised wheelbase x added weight on scale / distance raised ] x overall weight