What a camshaft is and why identification matters
A camshaft is a shaft inside your engine with egg-shaped lobes that push on valve lifters or rocker arms to open and close your engine's intake and exhaust valves at precise moments. The shape and size of those lobes, along with how many there are and how they're arranged, determine how your engine breathes — which affects power, fuel economy, and how the engine sounds.
Identifying your camshaft matters because if you're rebuilding an engine, buying a used one, or troubleshooting a noise, you need to know what you have. A camshaft from a different engine, year, or performance level won't work the same way in your vehicle. Mismatched camshafts can cause rough idle, poor fuel economy, valve timing problems, or engine damage.
The good news: camshaft identification usually comes down to reading a part number stamped or cast into the shaft itself, then cross-referencing that number with manufacturer records or a parts catalog.
Key Takeaways
- Camshafts have a part number stamped or cast into the shaft that identifies the exact cam — write this number down before you search for information about it.
- The number alone tells you the engine it came from, the year or year range, and often whether it's a stock or performance cam.
- You can cross-reference the part number using the manufacturer's parts catalog, a machine shop, or online forums dedicated to your vehicle brand.
- If the number is worn off or illegible, a machine shop can measure the lobe height and duration to narrow down what you have.
- Camshafts are not interchangeable between different engine sizes or generations, even if they look similar.
Where to find the part number on your camshaft
The part number is usually stamped or cast into the camshaft itself, most often on the front end (the end closest to the timing chain or belt) or along the shaft between lobes. On some engines it's on the rear end. The number may be a series of digits, letters, or both — for example, "350-1234" or "LT1-CAM-89".
To locate it, you'll need to remove the camshaft from the engine or at least access it well enough to see the shaft clearly. This usually means removing the valve cover and timing cover. Use a flashlight and look along the entire length of the shaft. If the number is faint, try rubbing the area gently with a wire brush or cloth to clean away oil and corrosion.
Write down the exact number, including any letters or dashes. Even a single digit wrong will lead you to the wrong cam. Take a photo of it too, in case you need to show it to a machine shop or forum.
How to read and decode the part number
Part numbers vary by manufacturer, but they usually follow a pattern. The first digits or letters often indicate the engine family or displacement (like "350" for a 350-cubic-inch engine). The middle section often codes the year or year range. The last digits may indicate whether it's a stock cam, a performance cam, or a specific variant for automatic or manual transmission.
For example, a Chevrolet small-block number like "14102050" might break down as: "14" (engine family), "10" (year code), "20" (specific process), "50" (variant). A Ford number like "C6OE-6015-B" uses letters for year (C6 = 1966) and letters at the end for revision level.
The exact decoding system depends on the manufacturer. Chevrolet, Ford, Mopar, and others all use different schemes. This is why the part number alone is usually enough — you don't have to decode it yourself. You just need to match it to a catalog or database.
Using manufacturer catalogs and parts databases
The fastest way to identify your camshaft is to enter the part number into the manufacturer's official parts catalog or a licensed parts retailer's database. Chevrolet, Ford, Dodge, and other major manufacturers maintain searchable catalogs online or through dealers. Enter the part number and the database will tell you the engine it fits, the year or years, and often a description like "stock" or "performance" or "high-lift".
If you don't have access to the manufacturer's catalog, try a major parts retailer like Summit Racing, Jegs, or RockAuto. These sites let you search by part number and will show you what vehicle and engine the cam is for. You can also call a local machine shop or performance shop — they often have access to multiple manufacturer databases and can look it up over the phone.
Write down everything the database tells you: the engine size, the year or year range, the valve lift (how high the valve opens), the duration (how long the valve stays open), and any notes about performance or process. This information helps you understand whether the cam is stock or modified, and whether it will work in your engine.
What to do if the part number is worn off or missing
If the number is completely illegible or was never stamped, a machine shop can measure the camshaft to narrow down what it is. They use a dial indicator to measure the height of each lobe (called lobe lift) and count how many degrees of crankshaft rotation each lobe occupies (called duration). These measurements can be compared to known camshaft specs to identify it or at least determine what engine family it came from.
This process takes time and costs money — usually $50 to $150 depending on the shop — but it's worth it if you're unsure. Bring the camshaft to the shop in person if you can, so they can measure it directly. If you can't, take clear photos of the shaft from multiple angles and include any other identifying marks or stamps.
Another option is to post photos and measurements on forums dedicated to your vehicle brand. Enthusiasts and rebuilders often recognize cams by sight or can help you measure correctly. Be specific about the engine size and year of the vehicle the cam came from, if you know it.
Why camshaft specs matter for your engine
Once you know what camshaft you have, the specs tell you how it will behave in your engine. A stock camshaft is designed for everyday driving — it opens and closes valves in a way that balances power, fuel economy, and smooth idle. A performance or high-lift cam opens the valves higher and keeps them open longer, which allows more air and fuel into the cylinder and more exhaust out. This increases power at higher RPMs but often makes idle rough and can hurt fuel economy at low speeds.
The lobe lift is measured in inches or millimeters — a stock cam might have 0.400 inches of lift, while a performance cam might have 0.500 inches or more. The duration is measured in degrees of crankshaft rotation — a stock cam might be open for 200 degrees, while a performance cam might be 230 degrees or more. These small differences have big effects on how the engine runs.
If you're installing a camshaft in an engine it wasn't designed for, or if you're rebuilding and want to change performance characteristics, understanding these specs helps you choose the right replacement or decide whether to modify other parts (like the intake manifold, carburetor, or ignition timing) to match.
Common camshaft identification mistakes to avoid
One common mistake is assuming that two camshafts are the same because they look similar or came from the same engine family. A 1970 Chevrolet 350 cam is not the same as a 1985 Chevrolet 350 cam, even though both fit a 350-cubic-inch engine. The part numbers are different, and installing the wrong one will cause problems.
Another mistake is confusing the camshaft with the crankshaft or other rotating parts. The camshaft is shorter, thinner, and has the distinctive egg-shaped lobes. The crankshaft is much thicker and has rounded throws. If you're not sure which is which, ask a machine shop or look at a diagram of your engine.
A third mistake is trusting a verbal description from someone selling a used cam. Always get the part number in writing and verify it yourself. "It's from a 350" or "it's a performance cam" is not specific enough. The part number is the only reliable identifier.
Frequently Asked Questions
Can I use a camshaft from a different year if it's the same engine size?
Not reliably. Even though both fit the same engine displacement, the part numbers are usually different and the specs may vary. A 1970 cam and a 1985 cam for the same engine will have different lobe profiles, and installing the wrong one causes rough idle, poor performance, or valve timing issues. Always match the part number, not just the engine size.
What's the difference between lobe lift and valve lift?
Lobe lift is the height the camshaft lobe itself rises, measured at the lobe. Valve lift is how far the valve actually opens, which depends on the lobe lift and the rocker arm ratio. A lobe with 0.400 inches of lift might produce 0.500 inches of valve lift if the rocker arm ratio is 1.25:1. The part number and catalog specs usually list lobe lift, but you need to know the rocker arm ratio to calculate actual valve lift.
How do I know if a camshaft is stock or performance?
The part number and catalog description usually say "stock," "performance," "high-lift," or similar. You can also compare the lobe lift and duration specs to known stock specs for that engine. Performance cams have higher lift and longer duration. If you're unsure, a machine shop can measure the lobe and tell you whether it's mild, moderate, or aggressive.
Can I identify a camshaft just by looking at it?
Not accurately. Two cams can look very similar but have different specs and part numbers. The only reliable way is to read the part number stamped on the shaft or have a machine shop measure it. Visual inspection alone leads to mistakes.
What if the camshaft came from a junkyard and has no paperwork?
Find and read the part number on the shaft itself. If it's illegible, take it to a machine shop for measurement, or post clear photos on a forum for your vehicle brand. Include the engine size and year if you know it. Enthusiasts can often identify cams from photos or help you measure correctly.