If it's not really about tuning or wiring. Then it belongs in here.
Curious to know
the rule of tomb when determining the best gear ratio in your gearbox for your track (Road Race )
The gear ratio with the most torque to the drive wheels will deliver the maximum acceleration as long as the wheels don't slip. The top gear (and/or final drive ratio) should be selected with the maximum speed you will need to see occurring just beyond the power peak.
Usually you are constrained by available gear ratios for a particular gear box.
I wrote an app for the iPhone/iPad that calculates the torque in each gear for a given engine, then figures out at what RPM you should shift to maximize the torque to the drive wheels. I use this info to program the gear-dependent shift light on my dash. If interested, search the Apple App Store for "Shift RPM"