Torque and horsepower are not unrelated.

They are related to each other as Power = Torque times Rotational Speed.

If HP, RPM and ft-lb are used as units, then the calculation is

Horsepower = (Torque)(RPM)/5252

It takes torque to rotate the wheels. It takes a high power to rotate the wheels fast as you can see from the equation.

Here is a reference Website:

http://vette.ohioracing.com/hp.html