Propeller pitch corresponds to transmission gear ratio in a road vehicle. It's true that an engine with greater low-end torque, like a big truck's diesel, will be better able to keep up revolutions, and therefore power output, at low rotational speed. In road terms, we would say that it will not "lug" or "bog down" in the way a less torquey engine might if it were not provided with a sufficiently low gearing. A constant-speed prop is analogous to a continuously variable transmission, adjusting engine speed to provide the desired horsepower at all times. A car or truck with such a transmission, or with a sufficiently wide range of closely-spaced gears, would climb a hill rapidly even if it lacked low-end torque, because it would be able to keep its engine speed, and therefore its power output, high. It is not true that, given suitable transmissions, of two vehicles of equal horsepower the one with the higher torque will climb better. Climb is all about horsepower, not torque; in fact, the very definition of horsepower is based on the rate at which a weight can be raised.