[bmalone]

Rarely, if ever can you expect to bolt four different types of things on an engine and EACH one is going to provide X additional HP. It doesn't work that way. In order to realize horsepower gains, the components must work TOGETHER to complement the whole--and the types of changes should complement what the engine is built for--torque, high rpm power, etc.

AN IC engine is a like an air pump--the more mixture that can flow through it--the more HP. That's why cam (determines how far and long the valves open), and head work--or more efficient heads (more flow again) will result in more HP. And adding cubic inches.