Pardon me if this is ignorant or has been answered before, but why do you strive to run your engine at exactly 14.7:1 AFR? Car manufacturers today only run at 14.7 because it produces the lowest combination of the regulated exhaust emissions. (Read: not the lowest level of some of the gases when measured individually, but the lowest point when the gases are averaged together.)
This is the best chart I could find in a hurry. It doesn't show NOx and CO2, but the NOX curve is roughly at its lowest point at 14.7 as well. Obviously, the more efficient you make combustion, the more CO2 you produce, and its curve is highest at 14.7. (HC + O2 = H2O + CO2.) One of my instructors at trade school often said, "The only reason anything has changed on cars since the 70s is fuel economy and emissions!" He'* mostly right, too.
Anyways, where was I going with this? Oh yeah, peak power is actually gained at a richer air/fuel ratio, around 12.5/13:1. A richer ratio is also an excellent KR killer too. Many racers run at 12 to 1, and most powersports products (Seadoos, ATVs, etc) run a similar ratio too.
Is it for fuel economy? Or is it because we all use the factory PCM to control our engines, which still wants to run 14.7:1?
Not trying to insult anyone, by the way, or step on any toes, just trying to stimulate some interesting conversation.