[blykins]

You can think of carb sizing in extremes.

A very small carburetor would offer great throttle response but would be really down on power. The engine would be able to create a great signal but the carb itself would be a restriction.

A very large carburetor would have horrible throttle response and you would find yourself adding jet to try and compensate for the lack of signal. It would probably make more horsepower/torque, but it would be at the top of the rpm range.

Your goal for a street car is to hit the middle of that spec. Great throttle response with the ability to feed the engine it's on.