how does torque and horsepower differ on car engines?

Torque is the the work (W) done by a force (F) acting thru a distance (s) of feet. Itis measured in Foot-Pounds.

The torque from an engine is delivered via the driveshaft to the rear axle, and it determines how much of a load the wheels will allow the vehicle to pull.

The horizontal force the wheel can push against the ground with is (F), and the radius of the wheel is (s) = Foot - Pounds.

Horsepower on the other hand is simply Torque / time = Foot - Pounds/Second

or it is the rate at which work (W) is done, or the rate that torque is delivered to the rear wheels.

Gasoline engines are usually designed to operate at higher speed (RPM's), than diesel engines, so they develop more Foot-Pounds/Second, or horsepower than diesel engines do. But diesel engines are capable of producing more Foot -Pounds, or torque, or work than gasoline engines, however they operate at a lower speed, therefore deliver less horsepower.

I have the power but I can't torque about it.

check out www.howstuffworks.com, they gave a great answer when i asked the same quistion :)