What Does It Mean If A Car Is Cammed

Overview

A car that is described as “cammed” has undergone a modification to its camshaft, the component that controls the opening and closing of the engine’s intake and exhaust valves. In internal combustion engines, the camshaft’s lobes push against valves to admit air and fuel and expel exhaust gases. Aftermarket camshafts or reground factory cams are designed with altered lobe profiles—changing lift (how far the valve opens), duration (how long it stays open), and lobe separation angle. These changes shift the engine’s power band toward higher engine speeds, often increasing peak horsepower at the cost of low-end torque and idle smoothness. A distinct symptom of a cammed engine is a rough, loping idle and a more aggressive exhaust note. The term is most common in the context of American V8 muscle cars, but applies to any modified engine with an upgraded camshaft.

History / Background

The practice of modifying camshafts dates to the early days of automotive racing in the 1910s and 1920s, when engineers discovered that altering valve timing could significantly increase engine output. In the post–World War II era, the hot rod and drag racing cultures popularized cam swaps as a relatively affordable way to gain power. By the 1960s, aftermarket cam manufacturers such as Crane Cams, Isky Racing Cams, and Comp Cams offered a wide range of profiles tailored to street and track use. The term “cammed” entered enthusiast vernacular to describe vehicles running a non-stock camshaft. Over subsequent decades, advances in computer-aided design and variable valve timing have made fixed-profile cam swaps less common on modern engines, but the practice remains prevalent among hobbyists building classic cars, muscle cars, and dedicated race vehicles.

Importance and Impact

Camming an engine can dramatically alter its personality. A well-chosen performance camshaft can unlock substantial horsepower gains, often 30–100 hp or more depending on the engine and supporting modifications. This has made cam swaps a cornerstone of budget performance building. However, the impact extends beyond power: a cammed engine typically idles at a lower and more unstable speed, producing a characteristic “lope” that many enthusiasts find desirable. The trade-offs include reduced fuel economy, increased exhaust emissions, and diminished drivability in stop-and-go traffic. In the aftermarket industry, camshafts represent a significant product category, and the term “cammed” has become a badge of honor among gearheads, signaling that a vehicle is built for performance rather than comfort or economy.

Why It Matters

For anyone buying a used performance car or considering engine modifications, understanding what “cammed” means is essential. A cammed car may require higher-octane fuel, more frequent valve adjustments, and a tuned engine control unit (ECU) to run properly. It may also fail emissions tests in regions with strict regulations. Conversely, a properly set up cammed engine can deliver a thrilling driving experience and increased resale value among enthusiasts. Recognizing the signs—rough idle, choppy exhaust note, and a tachometer that fluctuates at idle—helps buyers and sellers accurately assess a vehicle’s condition and history.

Common Misconceptions