Err...does that take combustion efficiency into account? a typical gas engine puts less than 20% of the energy it consumes out the driveshaft.
It doesn't take overall efficiency, volumetric efficiency, or ideal A/F ratio for whatever gas you're running (like say modern pump ethanolated garbage) into effect at all. Figured I'd just toss out the 'on a blackboard only' numbers just because that's what I had on that page of my notebook instead of piling on all the other details that VERY quickly complicate the mess. I've got a couple perl scripts that jumble the numbers for me, as I learn new math I add to the sim. Haven't made much progress lately though, seems buying a house slowed me down.