stock49,
I like your thought process. To improve your analysis you need to add volumetric efficiency. VE is how much mixture is actually trapped in the cylinder when the intake valve closes divided by the amount that could be if the valve closed at exactly BDC and wide open throttle.
VE will be higher at low speed open throttle compared to high speed closed throttle.
Engine performance equation: Brake HP = fuel heating value x fuel/air ratio x inlet density x suction volume x volumetric efficiency x indicated efficiency x mechanical efficiency x engine speed.
The value of this equation for a hot rodder isn't to start from scratch. Rather it is to understand the effect of changing one of the variables.
