Not sure if is was mentioned, but horsepower is a linear calculation derived from torque, which is non-linear, or rotational measure since an engine generates it's power by rotating the crankshaft.
HP = Torque x RPM รท 5252 (this is why torque always equals HP at 5252 RPMs)
In other words, torque is what matters when towing a load, and it's especially important at what RPM it's made. The more it makes earlier, the better. If you have to turn a higher RPM to generate the same amount of work, you'll be using more fuel to do it because parasitic loss increases as RPMs increase.
Now if you're talking about winning a drag race, that's a whole other story.
