Cylinder head ports allow air and fuel to travel through the cylinders. The more cylinders there are in a car, the more power it has. Cylinder head porting is when engineers reshape the ports to improve efficiency by removing flaws that come from the factory. It also reduces restrictions in the engine's intake and exhaust tracts, allowing more air and fuel into the cylinders, thus increasing horsepower. The cylinder head porting process is so intricate and complex that it takes a true craftsman with a lot of patience to get it right.
Some tracks are faster than others, some are longer.