* The specific camshaft: Different camshafts have different profiles (duration, lift, lobe separation angle), which drastically affect power output. A mild cam might only add a few horsepower, while an aggressive cam could add significantly more—or even *reduce* power if not properly matched to other engine components.
* The engine itself: The existing engine's characteristics (displacement, compression ratio, intake and exhaust system, etc.) heavily influence how much benefit a camshaft upgrade will provide. A cam designed for a high-performance engine won't necessarily work well in a stock engine, and vice-versa.
* The tuning: After installing a camshaft, the engine often requires retuning (e.g., adjusting fuel delivery and ignition timing) to maximize power and prevent damage. Improper tuning can negate or even reverse the horsepower gains.
* Other modifications: Other modifications, such as headers, exhaust, intake, and heads, interact with the camshaft. The cam's effect will depend on the presence and type of other performance upgrades.
In short, while some camshaft upgrades might yield a modest 10-20 horsepower increase, others could result in gains of 50 horsepower or more. Conversely, a poorly chosen or incorrectly installed camshaft could *decrease* horsepower. You need to consult resources specific to your engine and planned modifications to get a realistic estimate.
