The way to look at torque properly is to graph wheel torque vs miles per hour for all gears, then take the area under the combined curve from say 25mph to 125mph...(appropriate race speeds for car and tracks)
This is how one chooses the correct gear shift points, tire sizes, and final drive ratio. Once you have a torque curve, it is realatively easy to do in Excel. Even easier if you have the data output from a Dyno. Anything else is just guessing!