Originally Posted by Amerkin
You have this completely backwards; a flat and long torque curve allows you to take advantage of GEARING, which is how the "torque" actually gets to the ground. If you have a car with a 25% higher redline than another car you can effectively make 25% more torque to the ground and still shift at the same wheel speed. In other words, the high RPM allows you to take advantage of gearing - which raises your torque to the wheels.
Besides that - as Sticky said, torque means nothing. It is a component of power, however you can have torque without power (e.g. using a 3 foot wrench on a stuck bolt; I weigh 200 lbs, stand on the end - I just applied 600 ft-lbs of torque, but made no power) - it's not until you spin the bolt (e.g RPM) when power is made. Torque made at high RPM is what makes for a proper race car. I cannot think of anyone that would disagree with this.
To sum up and simplify without gearing - it's the TOTAL AREA underneath the power curve divided by weight that makes car A faster than car B with smaller area.
Diesels make a ton of torque, but they cannot spin that torque at high RPM, so they are slow. You had it completely backwards. "