Many variables determine the rpm range and torque curve – the "powerband" of an engine, including cubic inch displacement, cylinder head characteristics, intake manifold, camshaft specifications and others. Note that larger displacement engines require more duration than smaller ones because they require more air/fuel mixture to fill their larger displacement cylinders.

The most important aspect of camshaft (and other component) selection is to have your specific rpm "goal" in mind before you begin to select engine parts. A camshaft should be close to the last item on your list –chosen to match all of the other performance pieces on your engine. Remember that the best way to select a camshaft is to ask an expert to help you select the right camshaft based not only on the size of your engine, but on your entire combination of parts.

When seeking assistance in selecting a camshaft, it is important that you can provide the weight of your vehicle, transmission type, converter stall speed, rear end ratio, engine displacement, compression ratio, and whether it will be normally aspirated, or if you intend to run a power adder such as nitrous, a turbocharger, or a supercharger. Each of these variables must be considered when choosing a cam, and the more accurate the information – the better your new camshaft will perform.