[olddog]

Torque is a rotational force.

Horsepower is a rotational measurement of work, which takes into account the torque, the distance (in revolutions), and the time period.

If you measure 500 Hp at the wheels at a given speed, it doesn't matter how it was made. The car will accelerate the same from that speed. The engine could be developing 5000 ft-lb at 525.2 rpm, or 500 ft-lb at 5252 rpm, or 50 ft-lb at 52520 rpm (ignoring drive train losses). Obviously there must be different gear ratios to accomplish this.

To put it into perspective, if the Hp to the wheels is the same across the wheel speed range in each gear, it does not matter if it is a big block turning lower rpm or a small block turning higher rpm, assuming all other factors are equal (weight, balance, traction, etc.)