Last month we showed what gains were available from three aftermarket Three-Valve intake manifolds in naturally aspirated trim. This month we're going to try the same three intakes, only now we'll see ...

Your intake manifold. It takes in air and sends it to your engine's combustion chamber. This is basically the start of the combustion process. After all, you can't have combustion without air.

If you are any kind of gearhead or have worked with engines for even a little while, then you are likely familiar with the rules of thumb when it comes to intake manifolds and horsepower. The main ...