The Comprehensive Guide To GM Camshaft Identification Numbers

Selecting the proper camshaft is crucial if you want to improve the performance of your GM engine. Choosing a GM camshaft identification number with so many available can be difficult. 

We’ll walk you through recognizing GM camshaft identification numbers in this post and help you comprehend the important details they include.

We’ll also review some of the most typical issues that GM camshafts can have so you’ll know what to watch out for. So let’s get going!

About GM Camshaft

gm camshaft identification numbers

What Is It?

One crucial part of a crate engine is the camshaft. It regulates how the engine’s valves open and close.

An internal combustion engine uses an earlier model camshaft, a cylindrical rod often constructed of metal, to control other engine parts.

The camshaft in a GM engine chooses the best timing cover and length of the valves’ action, which impacts the engine’s overall performance.

GM offers a variety of camshaft types, including hydraulic, solid, and hydraulic roller camshafts.

When upgrading your engine, you can ascertain detailed engine upgrade advice and the precise type of high-performance camshaft you require and make an informed selection by knowing the GM camshaft identification codes.

Synchronicity And Shape

A camshaft’s synchronization is defined as the exact time and length of the valve operation. It must be precisely timed to the spinning of the engine.

Any timing variation from the ideal range can negatively impact engine performance. The camshafts are linked to the crankshaft’s rotation by a timing belt to guarantee this timing.

Additionally, a camshaft’s geometry is an important factor in affecting engine performance. The stock cam lobe’s shape influences the average duration time and lift of the lobe separation angle.

A simple rod or shaft with shaped lobes along it makes up a camshaft. The factory cam’s form allows it to act on a valve or switch to the extent of its severity when the shaft is rotated.

How Do Camshafts Work?

Camshafts function by regulating how the block engine’s valves open and close. They are in charge of letting fuel and air in and exhaust gases out.

A timing chain or belt connects the engine’s crankshaft to the camshaft specs. Typically, a timing chain links the custom 3-bolt camshaft to the crankshaft.

The camshaft’s lobes push against the valve lifters as it turns, causing the valves to open and close at just the right times.

The size and shape of the custom-ground camshaft lobe determine the amount of lift and length of the valve activity.

How to Identify GM Camshaft Identification Numbers?

camshaft identification numbers

The ideal GM cam identification numbers for your engine can be found in various ways, including visually analyzing the component and looking up the model prefix, grind number, and exhaust number.

You can even use an analog system to decode these data and ensure you pick the appropriate part for your GM engine.

Using Your Eyes

Inspecting the component with your eyes is the simplest and easiest approach to determine the GM camshaft identifying numbers.

Near the distributor drive gear, many GM camshafts have an identification number etched or engraved onto the camshaft.

This identification number is made up of letters and digits that describe the characteristics of the camshaft.

Two different kinds of cameras don’t use lenses; you can tell them apart just by looking at them. They have a flat tappet cam with a 0.050-inch tappet lift.

The precise sort of camshaft you have can be identified by carefully inspecting the engine cam and noting the identifying number.

It is a quick and simple technique to tell if a camshaft is from GM.

Model Prefix

Examining the model prefix is another method of identifying GM camshaft identification numbers.

The first component of a camshaft number is the model prefix, which varies by model. For example, 93 – 95 models and 96 – 97 models have different model prefixes.

The initial group of letters or numbers in the identification number, known as the “model prefix,” identifies the engine family and camshaft.

For instance, a camshaft made for a small-block Chevy engine code has the model prefix “LT1”.

By knowing the model prefix, you can narrow your search for the precise camshafts made for your engine builders. 

Grind Number

Another vital piece of information that helps you identify GM camshaft identification codes is the grind number.

The valve lift and duration are controlled by the camshaft lobes’ precise size and shape, as described by the grind number.

Each number can be interpreted and signified differently. For instance, the first three-digit value shows the average duration of the cam lobe design.

For example, the camshaft profile designated for a small-block Chevy engine model is indicated by the grind number “XE274H”.

The “XE” stands for the series, while the “274” represents the camshaft’s claimed duration in degrees. The “H” designates a hydraulic camshaft, which employs hydraulic lifters.

Exhaust Number

How to identify an unknown camshaft? The exhaust number describes the precise dimensions and form of the camshaft’s exhaust lobe.

You can choose the best camshaft for your needs by looking at the exhaust number to see if the camshaft is optimal for your engine heat’s exhaust duration by using the exhaust valve diameter wire.

The exhausting number is revealed by seeing 266/288. Through the use of a lifter body diameter, these quantities and piston styles can be determined.

As an illustration, the exhaust number 30-30 camshaft denotes a particular camshaft profile made for a small-block Chevy engine plant.

The numeral “30” indicates the lift of the exhaust lobe, and the number “30” denotes the length of the exhaust lobe in degrees.

Using An Analog System

When determining GM camshaft identification numbers, an analog system can be useful.

You may precisely measure the timing and duration of the camshaft using analog devices, such as a dial indicator and a reluctor wheel.

To use this procedure, you must carry out a few tasks, like measuring a few diameters and comparing them to the database.

To determine your precise type of camshaft, cross-reference this information with GM’s cam specs.

GM Camshaft Common Problems 

chevy camshaft identification numbers

Check Engine Light Is On

The appearance of the check engine light is one of the most frequent issues with GM camshafts. Numerous problems, including a broken camshaft position sensor, may be to blame.

It’s crucial to have your engine checked by a trained mechanic if you see the check engine light on your dashboard.

Your engine size could suffer additional harm and lose go-to performance if you ignore this problem.

Loss Of Power

Loss of power is another issue that GM camshafts frequently encounter. Numerous problems, such as a worn or damaged camshaft and nitrous oxide.

A worn lifter, or a rocker’s arm, may be to blame.

It’s critical to check your basic engine configuration and intake systems if you notice a drop in performance or power.

To adequately diagnose it, you’ll need a scanner to track the cam/crank timing or how much it varies at various RPMs. It will probably need chains when it has many miles on it.

Debris In The Engine Oil

Debris in the engine fluid is another frequent issue with GM camshafts.

It can break down due to prolonged use, dampness, water damage, and oil buildup on the V6 90º engine with stock rockers.

Metal particles could circulate inside the balance shaft engine speed due to a worn camshaft lobe.

When you check the oil flow in your machine, you probably won’t be able to see the metal, but when you drain the oil through the sump pan plug, the metal will be exposed.

Cylinder Misfire

Because the faulty lobes regulate the entire valves, damaged camshaft gear poles will change the cylinder aluminum head bolt size and likely result in cylinder misfires and change the cylinder head design because the dual valve spring won’t open and close in time.

It will result in poor ignition and a high-flow block cylinder head bolt style, hindering the air-fuel mixture from properly igniting and drag racing.

Your car can jolt or shake violently, lose power, have high bore spacing, have a bigger piston volume and brian nutter, use more gasoline than usual, and emit more pollution.

When the fuel pump lobe is timed by some manufacturers using the cam sensor, the car experiences more than just a misfire.

Loud Ticking Sounds

Another bad news with GM camshaft installation is loud ticking noises. A worn or damaged camshaft life may be to blame for this, resulting in errors in valve train or lifter noise.

The factory valve spring’s clearance will rise with camshaft lobe wear, making them louder.

However, locating their origin might be challenging because these sounds are frequently sporadic.


What Is The Difference Between A Camshaft And A Crankshaft?

A camshaft is a cylindrical shaft that regulates a block V8 engine’s valve opening and shutting.

In contrast, a crankshaft main journal is a lengthy, rotating shaft that transforms the engine bolt’s pistons’ reciprocating motion into rotational motion.

What Are The Symptoms Of A Bad Camshaft Position Sensor?

The way the car drives has changed.

Your car may be experiencing camshaft position sensor failure if it idles erratically, stalls regularly, loses power, gets poor gas mileage, or accelerates slowly.

How The Camshaft And Crankshaft Are Connected In The Engine?

Either belts or chains are used to connect the two shafts.

The distributor gear ratio between the two shafts in a four-stroke engine block is 1:2. The crankshaft rod journal must rotate twice for every camshaft revolution.


The proper camshaft for your engine must be chosen, which requires knowing the GM camshaft identification numbers.

Understanding the exact characteristics of your camshaft is crucial to obtaining the best engine performance, whether you utilize visual inspection, model prefix, grind number, exhaust number, or an analog approach.

GM camshaft identification numbers can be handled proactively to guarantee your engine functions smoothly for many years.

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