[Bob In Ct]

David:
If you are measuring engine RPM the formula will yield the HP at the rear wheels. It does not matter what the rear end ratio is, the tire size or the gear. That being said, I would expect the best numbers to be in 4th gear (1:1) would all fluids warm.

If the engine is turning 5,252 RPM and the torque reading is 450 FT-LBS, you have 450 HP at the rear wheels.

Bob