Camshaft Specs Explained: What They Mean and How They Affect Your Engine

When it comes to modifying or understanding your engine, few parts are as influential as the camshaft. Swapping or tuning a camshaft can drastically change the behavior of your car—turning a mild street cruiser into a lopey, track-ready monster.

But to do it right, you need to understand what the camshaft specs mean and how each affects power, torque, driveability, and engine behavior. Let’s break down the key terms and what happens when you change them.

What Is a Camshaft?

The camshaft controls the timing and duration of the opening and closing of the engine’s intake and exhaust valves. It directly impacts how air and fuel enter the combustion chamber—and how exhaust gases exit.

In performance applications, camshaft design is key to tuning your engine for low-end torque, high-end horsepower, or a balanced power curve.

Key Camshaft Specs and What They Mean

1. Duration (Advertised and @ .050")

• Definition: The amount of crankshaft rotation (in degrees) that a valve remains open.

• Advertised Duration: Measured from the very beginning to the very end of valve movement (includes “ramp”).

• Duration @ .050": Measures only the "real" valve motion (industry standard). More accurate for comparison.

Effect of Changing Duration:

• Shorter duration (e.g. 210–220° @ .050"): Better for low RPM torque and smooth idle.

• Longer duration (e.g. 240–260° @ .050"): Moves the powerband higher in the RPM range—more top-end power but rougher idle and less low-end torque.

2. Lift

• Definition: How far the valve opens (measured in inches).

• A higher lift allows more air/fuel to enter or exit the chamber.

Effect of Changing Lift:

• Higher lift = more airflow = potential for more horsepower.

• Too much lift without proper springs/valvetrain upgrades = valve float or component wear.

• Most street cams stay under .600” lift, while aggressive race cams can go higher.

3. Lobe Separation Angle (LSA)

• Definition: The number of crankshaft degrees between the peak of the intake and exhaust cam lobes.

• Common range: 106° to 114°

Effect of Changing LSA:

• Tighter LSA (e.g. 106°–108°):

  • More overlap (both valves open at the same time)

  • Rougher idle, aggressive sound (“cammed lope”)

  • More mid-range power, less vacuum

• Wider LSA (e.g. 112°–114°):

  • Smoother idle

  • More vacuum (better for power brakes, street manners)

  • Broader power curve, better drivability

4. Overlap

• Definition: The time (in degrees) when both intake and exhaust valves are open.

• Determined by duration and LSA.

Effect of Overlap:

• More overlap = better high-RPM power and that classic “cammed” sound.

• Less overlap = smoother idle, better fuel economy, and emissions.

How Cam Specs Affect Different Builds

Mild Street Cam

• Duration @ .050”: ~210–220°

• Lift: ~.500”

• LSA: 112°–114°

• Result: Good idle, strong torque, perfect for daily drivers or mild upgrades.

Street/Strip Cam

• Duration @ .050”: ~225–235°

• Lift: ~.550”–.600”

• LSA: 110°–112°

• Result: Noticeable lope, stronger mid-range, needs supporting mods (springs, tune).

Race/Track Cam

• Duration @ .050”: 240°+

• Lift: .600”+

• LSA: 106°–110°

• Result: High RPM power, lopey idle, weak low-end, rough manners. Requires significant engine mods.

Real-World Scenarios: Which Cam Is Right for You?

Daily Driver or Weekend Cruiser

You want smooth idle, usable torque, and reliability. A cam with moderate duration (216°), lift (.525"), and wide LSA (112–114°) gives great street manners with a little extra kick.

Street/Track Hybrid

Looking for a cammed sound and track-ready response? Go for a mid-230s duration, ~.550” lift, and a tighter LSA (~110°). Pair it with a good tune and stronger valve springs.

All-Out Race Build

All-in on horsepower? Think big—250°+ duration, high lift, tight LSA. Be ready for a lopey idle, vacuum loss, and high-RPM operation. Not ideal for the street, but unbeatable on the track.

Supporting Mods Matter

No cam works alone. You'll often need:

• Upgraded valve springs

• Pushrods and lifters

• ECU tuning

• Exhaust and intake improvements

• Stall converter (for autos)

• Gears or driveline upgrades (for aggressive builds)

Final Thoughts

Choosing the right camshaft is all about matching your goals to the right specs. A cam with wild numbers might sound mean, but if it doesn’t match your build, it can make your car slower—or just miserable to drive.

Always ask yourself:

• What do I use this car for?

• Do I care more about sound or performance?

• Can the rest of my setup support this cam?

Do your research, consult your tuner, and don’t be afraid to start mild and work your way up. A well-matched camshaft can completely transform your engine’s personality—and your driving experience.

Let me know if you’d like a chart of popular cam profiles or help comparing options for a specific vehicle!