Classic cars characterized by V8 engines and American muscle are known as CAM cars; these classic vehicles can often be found racing on race tracks or participating in SCCA Solo events as "cammed cars." Cammed cars refers to vehicles modified so their valves open and close differently - an upgrade that can make engines faster and more powerful, though understanding camming may require further research before proceeding with any such modification to your vehicle.
Camshaft lobes come in various shapes to open or close valves when the crankshaft turns. When your engine has a high-duration camshaft that holds open longer, your engine may sound rough at idle or produce an audible rattle when driving - this is due to working harder in moving air and fuel into its cylinders for intake.
Performance camshafts are engineered to add power by controlling how your engine's valves open and close. There are various methods you can employ to modify this mechanism such as using pulleys to alter timing or installing new camshafts; you could also change valve springs or use different intake manifold designs.
Cammed cars typically perform best at higher RPMs as it allows engines to reach their power bands faster, but increased valve opening times and timing may result in reduced fuel economy ratings. Also note that camming your car can be an intricate upgrade that requires expert tuning skills for maximum effectiveness.