LS6 Camshaft Upgrade Guide

Ever since Chevy put the LS6 inside the C5 Z06 Corvette, it has been a popular power plant for high horsepower builds. The robust 5.7L V8 makes 385-405 horsepower and 385-400 lb-ft of torque from the factory. Yet, anyone who has ever driven one will tell you they are begging for more. One of the most popular mods for the engine is an LS6 camshaft upgrade. Upgrading the stock cam to a performance cam will net increases in peak horsepower, improve the entire power band, and add a distinctive sound to the exhaust.

First, we’ll go over the basics behind what a camshaft does and how the stock cam performs, and then we’ll get into why you might want an LS6 camshaft upgrade and how to pick the best one for your build.

Camshaft Basics

A camshaft is one of the most important parts of an engine’s valve train. The valve train controls the opening and closing of an engine’s intake and exhaust valves, which allow air and fuel in and out of the engine. The purpose of the camshaft is to regulate when the valves open and close and for how long.

A camshaft is, as you might expect, a long shaft that has several “cams” or lobes on it. Each lobe corresponds to a valve on the engine, so an LS6 camshaft will have 16 lobes. The LS6 has what is known as an overhead valve (OHV) valve train with a “cam-in-block” camshaft. That means the camshaft sits inside of the block instead of on top.

Camshafts are controlled by a timing belt or timing chain which is connected to the crankshaft. As the camshaft spins, the lobes come into contact with lifters, which in turn push up and down on pushrods. The pushrods are connected to rocker arms, and the rocker arms themselves are connected to the actual valves.

As the pushrods actuate the rocker arms, the valve is pushed down and allows/expels air in and out of the engine. As the pushrods and rocker arms come back down, the valve is pushed back up and closes the intake and exhaust ports, stopping air/exhaust from coming in or out. A set of valve springs ensures the valve will stay in the closed position when not being pushed down by the rocker arm.

That in a nutshell is how a basic OHV engine’s valve train works. Check out the video below for a visualized animation of an OHV engine.

C5 Corvette LS6 Cam Specifications

Now that we know the basics behind how a camshaft works, let’s get into the different specifications camshafts have and what they mean for an engine’s performance. As we said, the purpose of the camshaft is to regulate the timing and length that the valves allow air and fuel in and out of the engine. The goal is to get as much air and fuel into the cylinder as possible, and then to quickly get the exhaust out of the cylinder after full combustion.

The three most common camshaft specs you will see are duration, lift, and lobe separation angle. All of these are referring to the “cams” or lobes on the camshaft. Larger lobes will mean a larger lift and duration, and a larger angle between them means a larger lobe separation angle (LSA), but we’ll go more into that below.

Camshaft Duration, Lift, and Lobe Separation Angle Explained

A camshaft duration is usually measured in degrees and is based on the rotation of the crankshaft. A higher duration means the valve is open for a longer period of time. Most camshaft durations are given in increments of 0.050” crankshaft rotation for continuity.

So a typical LS6 camshaft duration will say something like intake 220° @.050”, which means the crankshaft moves 220° while the intake valves are open. All modern engines are going to have intake and exhaust valves, so you will generally see two measurements per cam, one for intake and one for exhaust. Since the intake and exhaust cams are usually open for separate lengths of time, you’ll typically see two different numbers.

Camshaft lift is measured in inches and determines how much the valve opens. A typical camshaft lift will be something like 0.550”, and like the duration will have an intake and exhaust measurement.

The lobe separation angle determines the specific angle between the intake and exhaust lobes on the camshaft. An LSA of 0° would mean they are both facing the exact same direction and that both the intake and exhaust ports would open at the same time. Your typical LS6 camshaft will have an LSA of 114°, meaning the angle between the centerline of the intake and the centerline of the exhaust lobe are 114° apart. LSA also determines overlap between when the exhaust and intake valves are open, with a wider LSA meaning more overlap.

What Do Cam Specs Mean?

So what does all of this mean? A camshaft that has a longer duration and higher lift will allow more air into the engine for longer, meaning it will be capable of more power. A camshaft that has less duration and a smaller lift will restrict the amount of air coming into the engine.

The LSA is important too, because it will tell you about the car’s drivability. A narrower LSA will result in better low-end torque and increased peak torque, but at the expense of a narrower power band, increased cranking compression, poor idle, and higher cylinder pressures – making detonation more likely.

A wider LSA will decrease low-end torque and result in less peak torque, but will also idle smoother, decrease cranking compression, have a larger power band, and have lower cylinder pressure – which reduces the likelihood of detonation.

For all three LS6 specs – duration, lift, and LSA – you have to balance performance with drivability. If you are building something for the track that doesn’t need to have the smoothest idle or best drivability, a higher duration and lift cam with a moderate LSA will be best. If you still need daily driver performance and want to make some extra power, a more moderate duration and lift cam with a wider LSA will work the best.

C5 Corvette Stock LS6 Cam Specifications

The LS6 used two different profile camshafts during its production run. For its inaugural year in 2001, the LS6 used a cam that had an intake/exhaust duration of 204°/211°, with lift of 0.525”/0.525”, and a 116° LSA. From 2002-2005, it used a cam with an intake/exhaust duration of 204°/218°, with lift of 0.555”/0.551”, and a 117.5 LSA.

As you can see, the second cam was much hotter due to having more exhaust duration, greater lift, and a slightly wider LSA. The new hotter cam was partially responsible for the 20 horsepower and 15 lb-ft of torque increase in performance.

Choosing the Right Cam

Now, let’s get into optimal camshaft sizing for your build using the duration, lift, and LSA specifications we went over earlier. For budget builds and those looking to keep a largely stock handling profile, you will probably want to look at cams with a duration of 214°-225° with an LSA between 112°-115°. If you want a little more horsepower while still keeping pretty good drivability, looking in the 226°-240° with an LSA between 112°-114° will probably be optimal.

If you are really looking at turning up the wick and getting some serious horsepower, and you’re willing to sacrifice some low-load drivability, anything 241° and larger with an LSA between 110°-112° will be in your range. As for lift, for an aftermarket LS6 camshaft, you will want something between 0.550”-.615”. Higher horsepower builds will generally want more lift, but that’s not always the case.

Generally, the stock cam will make 400 whp with bolt-ons (cold air intake, headers/exhaust), cams between 214°-225° will add around 25-50 whp over stock. Cams between 226°-240° will add 50-75 whp, and cams larger than 241° will add 75+ whp over stock.

Keep in mind, a camshaft’s performance is determined by duration and lift, so just duration won’t tell the whole story. While the debate constantly rages, for most people lift will determine performance rather than duration. However, most cams are discussed in terms of duration rather than lift, hence our above guide.

Camshafts are some of the finickiest upgrades you can do. For many people, it takes 2-3 different cam swaps until they find a good balance of duration and lift. Like we said, it definitely changes how the car drives, and that can be both good and bad.

Upgrading the Rest of the Valve Train

Regardless of how hot of a camshaft upgrade you choose, you will need to also upgrade the LS6 valve train. No matter what, you will need to upgrade to stiffer valve springs, as the stock springs are barely capable stock. Some of the most popular valve spring upgrades are COMP 918 and 921, Manley’s Nextek, and Crane Duals.

Next will be pushrods. While you do not have to upgrade the pushrods, it is highly recommended – even on mild cam upgrades. The stock pushrods have been seen to flex at times under big loads, meaning disaster is lurking around the corner. Getting stronger aftermarket pushrods is cheap insurance that makes sure you’re getting maximum performance.

You can also upgrade the rocker arms as a precaution, and it’s good on larger horsepower builds (800+). Going with a rocker arm with a higher ratio than stock can add lift/duration and increase overlap, adding power. Many people also add the Trunion Rocker Arm kit, which converts the rocker arms to roller bearing rocker arms and adds reliability.

Upgrading the timing chain is pretty much standard for any cam upgrade, as the stock ones are known to fail. Upgrading the lifters is also a precaution that many people take when upgrading the cam and pushrods.

With these upgrades your cam swap will go smoothly. Early LS1 engines also need a new oil pump, but the LS6 has an upgraded one, so it’s not necessary.

LS6 Camshaft Upgrade Benefits

• +25-100 wheel-horsepower
• +25-100 wheel-torque
• Increased power band
• Distinctive “chop-chop” exhaust sound

By far the biggest benefit to a camshaft upgrade is going to be the added power. Depending on the cam profile you choose, you can add anywhere from 25-100 wheel horsepower and wheel-torque to your build. While some people will claim that cams only really make a difference on the top-end, that’s simply not true. The entire power band will generally get wider. On big cams where some low-end torque is lost, then generally the curve is still more favorable on the top-end.

Cams are great upgrades for naturally aspirated engines, but can also help on forced induction builds, too. Well-designed and optimized cams for the right turbo build can increase spool while sustaining more peak power.

Another “benefit” of a cam upgrade is the distinctive exhaust note from an upgraded cam. While small cams will keep the exhaust sounding relatively stock, larger cams will give the distinct “chop-chop” sound we all know and love. Especially through long-tube headers, most cam swaps sound absolutely fantastic on LS engines.

Camshaft ECU Tuning

The final thing we will go into is ECU tuning for your camshaft upgrade. On smaller cams you can get away without tuning, but the larger the cam the harder the time the ECU has compensating. If the ECU struggles to compensate, the engine will struggle to properly idle and stop from misfiring.

Getting your ECU tuned after upgrading your cam is a good idea to maximize performance while ensuring reliability. You don’t want to spend $600 upgrading your cam just to have an undrivable car.

LS6 Camshaft Upgrades Are the Best Bang For Your Buck

Upgrading the camshaft on the LS6 is a solid performance modification that nets some serious horsepower gains. Of course, as we just discussed, it’s not a modification to be taken lightly, and it really changes how the LS6 performs. Still, on the right builds, upgraded cams will make a world of difference and really improve your power band.

In this article, we looked at several different camshaft choices for your LS6 build. Make sure you keep our sizing guide in mind when picking out your cams, but it’s also a good idea to talk with the camshaft manufacturer yourself. Explain to them your power goals and work together to find the best cam for your build. Whether you’re looking for something mild and steetable, or something huge and race-only, you’ll be able to find what you’re looking for with our recommendations.

Let us know about your experiences with LS6 camshaft upgrades in the comments!