Generally wheel torque would be quoted in the gear that gives you a 1:1 (or close to) ratio. Hence in a lot of cars a dyno run will be done in 4th gear as high

Generally wheel torque would be quoted in the gear that gives you a 1:1 (or close to) ratio. Hence in a lot of cars a dyno run will be done in 4th gear as higher gears are generally overdrive gears. Also your calc is missing the final drive ratio.