Straight from the factory, the General Motors/Chevrolet LS1 engine already boasts some pretty impressive performance. Chevy put it inside the C5 Corvette and fourth generation Camaro SS and Z28, and it also found its way into the fourth generation Pontiac Trans-Am and Formula, as well as the 2004 GTO. Inside these cars, the LS1 produced 305-350 horsepower and made 335-365 lb-ft of torque. Yet, while the LS1 is already pretty capable stock, adding some LS1 upgrades can really open it up for more power.
This guide will cover the best mods and LS1 upgrades for your build. The 5.7 L V8 can handle some serious power, and it does very well with some modest airflow and fueling upgrades. However, we’re not gonna stop there, we’ll show you how to build everything from a moderate 375 horsepower build all the way up to a 1,000 horsepower monster.
LS1 Engine Basic Info for Modding
Let’s start with the basics before we get into actual LS1 upgrades. GM/Chevy produced the LS1 from 1997-2004, and it is a 5.7L naturally aspirated V8 engine. The LS1 was the first of GM’s third generation of small block V8s to be released, and it actually gave the engine series its more common name, the LS-series. The LS1 had an advertised compression ratio of 10.1:1, but most put it slightly higher at 10.2:1.
The compression ratio is well suited for boosted applications, and the LS -series of engines love forced induction. Both the head and block are made out of aluminum, which helps to shed weight while still maintaining strength. While it doesn’t make the LS1 indestructible, it definitely makes it robust and capable of withstanding some serious abuse.
The LS1 uses the LS-series cathedral-port cylinder heads. From 1997-2000, it used one set of heads, but from 2001-2004 GM/Chevy gave the LS1 the LS6 heads. The LS6 heads are known to be substantially better flowing than the LS1 heads, though GM/Chevy only reported a 5 horsepower increase. However, this is thought to be a conservative estimate for insurance reasons.
Modded LS1 Engine Power Limits
The LS1 engine, and the entire LS-series, is known to have pretty robust power limits. It’s generally thought that the LS1 block can withstand about 800 wheel-horsepower before it will struggle. That’s not always the case, as some people have run hundreds of horsepower more, but most people 800 whp is considered a reasonably reliable limit. You won’t get 50,000 miles out of it, but it also won’t break apart after just a few runs.
Internally, like the rest of the early LS-series, the LS1 pistons and rods are good until around 500 horsepower. The rods are stronger than the pistons, but it’s a good idea to upgrade both to stronger forged versions if you want to go past 500 horsepower reliably. At this stage, you will also want to add head studs. If your LS1 upgrades include the valve train, you’ll want to strengthen it with at least better pushrods and lifters.
Top 7 LS1 Upgrades
Our top 7 LS1 upgrades are:
- Upgraded Intake
- Long-tube Headers
- Intake Manifold
- Cylinder Head
- ECU Tuning
LS1 Naturally Aspirated Mods
For most, starting with simple bolt-on mods like an upgraded intake and long-tube headers are great first LS1 upgrades. They help improve airflow in and out of the engine, both in terms of volume and velocity, which is crucial for increasing power.
The next LS1 upgrade is for the intake manifold. The stock LS1 intake manifold leaves a lot to be desired, and is probably the worst in the entire LS-series. The original manifold from the 1997-2000 LS1 was so bad GM/Chevy gave it the LS6 intake manifold in 2001. While the LS6 manifold is an improvement, depending on your power level it might be worth an upgrade.
Now let’s talk about LS1 upgraded cylinder heads. As we mentioned earlier, the LS1 uses the LS cathedral-port style of cylinder head. While these are good for low-end torque, they really struggle for good flow on the top-end. Just like the intake manifolds, the initial LS1 cylinder heads were performed poorly enough that GM/Chevy upgraded them to the LS6 versions in 2001. Once again, while the LS6 heads offer better performance than the LS1 heads, there is still potentially room for improvement, as we’ll discuss below.
Another common mod is to upgrade the LS1 camshaft. Camshaft choices are important, as you’re going to have a trade-off between low-end torque and top-end performance. The right cam will get you a good tradeoff, and give you torque where you need it and power when you want it.
LS1 ECU Tuning and Blowers
ECU tuning is another important LS2 upgrade. While it might not seem crucial at first, tuning can make the difference between a good engine build and a blown engine. With tuning, you’ll be able to have optimized ignition timing and air-to-fuel ratios, as well as other parameters to help you take advantage of all your mods. If you’re going to be spending hundreds in bolt-ons, you’ll want to make sure to maximize your gains from them.
Finally, if you really want to take your LS1 build to the next level, you’ll want forced induction. A naturally aspirated LS1 peaks at around 500-550 horsepower for most builds. If you want more power, the most cost effective way is either a supercharger or a turbocharger.
1) LS1 Intake Upgrades
One of the best upgrades that applies to almost any naturally aspirated engine, including the LS1, is going to be an upgraded intake. The LS1 can see gains of 10-15 horsepower from just an intake alone. The stock intakes on most LS1 vehicles are pretty restrictive when you want to start increasing power, especially up top.
An upgraded intake will increase air flow while ideally also adding cooler air too. With the LS1, you have somewhat limited options for intakes. Most Corvette intakes will be of the ram air variety, as those often work best with the engine bay configuration. But, for other LS1 cars, you have the option of a true cold air intake, which is generally preferred.
The purpose of a cold air intake is to help grab cooler air from outside of the engine bay for better performance by relocating the filter placement, and to cut down on the restrictiveness of the OEM intake. A ram air intake, on the other hand, works by providing the quickest and least resistant path for incoming air. It won’t usually bring in colder air, but it does eliminate restriction and increases flow.
While the stock intakes generally perform okay, if you add any other bolt-ons like long-tube headers it often becomes a restriction point. Adding a freer flowing intake will improve throttle response, top-end power, and increase the engine noise. It also makes your engine bay look much better and more aggressive.
Best LS1 Intakes
It depends on your specific car model for the best intake for an LS1 upgrade. We recommend a cold air intake as one of the first mods you do. An important decision you’ll have to make is a closed vs open airbox. Open airboxes are more susceptible to heat soak, but they have improved airflow. Closed airboxes cut off some flow, but they also mitigate engine heat soak for longer, providing cooler air.
For the C5 Corvette, the intake is already at the front of the bay, so it’s pretty difficult to relocate the filter while improving flow. For that reason, on the Corvettes we recommend the Callaway Honker Ram Air intake. It is a ram style intake and not a true cold air intake, but it performs very well on the C5 Corvette. They claim gains of up to 16 horsepower, and for many people the Callaway Honker is the standard for C5 Corvette intakes.
For the ‘04 GTO with the LS1, we recommend the Cold Air Inductions GTO cold air intake. This intake includes a closed and insulated aluminum airbox and a 4” intake tube. The airbox has a clear top, so you can check the condition of your filter without removing anything.
Buy Here: C5 Corvette Callaway Honker Intake
2) LS1 Long-tube Header and Exhaust Upgrades
Next, let’s talk about upgrading the stock LS1 headers to long-tube LS1 headers. The OEM headers are made of heavy cast iron and are incredibly restrictive. They are also prone to cracking over time; for any serious build, upgrading the long-tube headers is an absolute must. The LS1 uses two headers, one per cylinder bank.
Long-tube headers replace the OEM exhaust manifold and exhaust back to the mufflers. Headers is essentially a term for aftermarket exhaust manifolds. Usually aftermarket headers are wider than OEM, typically made out of lighter 304 stainless steel, and are designed for optimal exhaust flow. All of this combines to reduce back pressure and reversion, while increasing exhaust scavenging.
The reduction in back pressure allows for better exhaust flow. Increased exhaust scavenging and reduced reversion means exhaust gasses are removed quicker and more clean air can enter the combustion chamber. This leads again to bigger and more sustained power.
You’ll also undoubtedly get a big bump in exhaust volume from long-tube headers. As you might expect, the big increase in piping and optional cats also really turns up the sound from the LS1.
Best LS1 Upgrades for Long-Tube Headers
Long-tube headers for the LS1 fall into one of two categories: catted or catless. While catless systems will produce a little more power, they are also not emissions compliant and will not pass inspection.
We recommend going with catted headers, because the power difference is pretty minimal and they are better for daily drivers.
Catted exhausts will be a little quieter, and they also smell 100% better. You should still be able to hit whatever your power goals are, even with a high-flow catalytic converter.
Our first recommendation on LS1 long-tubes are going to be from American Racing Headers (ARH). ARH is a very popular name in the LS-series exhaust industry, and they have been producing solid headers for many years. Their LS1 exhaust systems are available in several different primary sizes and are all made from 304 SS.
Next is from Kooks Headers for the C5 Corvette. The Kooks long-tubes are also catted, but they feature an x-pipe instead of a y-pipe like in the ARHs. The x-pipe setup has been shown to flow superior to the y-pipe setup, making the Kooks somewhat more desirable. Regardless of the long-tubes, you can see gains of up to 10-30 whp with headers on the LS1 by itself, and even more with tuning.
3) LS1 Intake Manifold and Throttle Body Upgrade
Now let’s look at the LS1 intake manifold. The purpose of an upgraded intake manifold is to increase the volume and velocity of air coming into the engine. Aftermarket LS1 intake manifolds have larger capacity plenums and runners, which allow more air into the engine.
Connected to the intake manifold is the throttle body. On the LS1, the stock throttle body is 78 mm. A larger throttle body increases the amount of air that can enter the intake manifold, and is often upgraded with the intake manifold.
The decreased restriction and increased flow from an upgraded LS1 intake manifold will allow for more peak power as well as a wider power band. Some manifolds are more designed for top-end power, while some focus more on the mid-range. Shorter runners will allow for more top-end power, while longer runners allow for more low-end torque.
Best LS1 Intake Manifold Upgrades
If you have the 1997-2000 LS1, you definitely want to upgrade your manifold. As we mentioned earlier, GM/Chevy gave stock 2001-2004 LS1 engines the LS6 intake manifold, and that is a great upgrade for earlier LS1s, too. It is a direct bolt on fit and will definitely improve performance.
For those looking for even more power, or if you already have the LS6 style intake manifold, the most popular option is the FAST LSXR LS1 intake manifold. The FAST intake is made from a polymer that is claimed to be both stronger and lighter than aluminum.
The FAST LS1 intake manifold has a 102mm throttle body, a massive 24mm increase over stock. However, it can also be used with 92 mm and 90 mm throttle bodies, as well as the stock 78 mm throttle body with an adapter. The Fast LSXR LS1 intake manifold is best suited for big horsepower LS1 builds, possibly using forced induction.
Buy Here: FAST LSXR LS1 Intake Manifold
4) LS1 Cylinder Heads Upgrades
Next on our list of LS1 upgrades is the cylinder heads. As we pointed out previously, the LS1 uses the cathedral-port style cylinder heads, which isn’t optimal for higher RPM flow. It does a great job of providing low-end torque, but if you’re wanting more top-end horsepower you’ll want other options.
One is porting of the factory LS1 heads, which does help a little bit. Porting essentially smoothens and rounds out the imperfections in the stock manifold, which helps increase flow and reduces air turbulence. Air turbulence is the antithesis of flow, and it will impede horsepower if it’s bad enough.
The next option is going with a larger cylinder head. You have a few choices, either you can stick with a higher flowing version of the cathedral-port heads, or you can upgrade to rectangular-port heads. It’s more cost-effective to go with cathedral-style, as they will bolt right on. But for the most power, the rectangular-style is king.
Top LS1 Cylinder Head Upgrades
For LS1 cylinder heads upgrades, we recommend the Livernois Motorsports Pro Series LS Cylinder Heads. These are cathedral-port style heads that vastly outflow the stock and LS6 heads. Livernois Motorsports is one of the biggest names in the LS engine building industry, and they have a very solid reputation after decades of quality workmanship.
The other recommendation we would make is if you are using a 1997-2000 LS1 to upgrade to the LS6 cylinder heads. While they won’t provide the same performance as the Livernois Motorsports heads, they are definitely better than the original LS1 heads. Like the intake manifold, GM/Chevy replaced the LS1 cylinder heads from 2001, a pretty good indication that the LS6 heads are much better.
5) LS1 Camshaft Upgrades
An upgraded camshaft is going to be our next recommendation for LS1 upgrades. The stock LS1 cam is fine for stock power levels, but if you’re looking at other bolt-ons then upgrading to a longer duration and higher lift cam is a good idea, too.
When upgrading camshafts, the things you are going to want to pay the most attention to are duration and lift. A higher lift means the valve opens wider, which means more air can get into the engine for more power. A longer duration means the valve will be open longer, again allowing for more air to enter the engine. Duration is measured in how many degrees the crankshaft turns while the valve is open, and lift is measured in inches from the valve to the head.
The trade-off for longer duration and higher lift cams is more top-end power at the expense of low-end torque. Especially if you’re building your daily driver, you’ll want a good balance between low-end torque and top-end horsepower. This will make your car still drivable at low engine loads in traffic, while allowing you to toast some rubber when you really need it.
Best LS1 Camshaft Upgrades
For LS1 camshaft upgrades we have two recommendations, both of them from Livernois Motorsports. The stock LS1 cam has different specs depending on the vehicle. The 2000 Corvette and early Camaro/Firebird had by far the hottest cam, but that was quickly reduced the following year.
The Livernois Motorsports Stage 2 has a lift 0.595” and the Stage 3 lift is 0.612”. The Stage 2 duration is 232° @ 0.050”, and the Stage 3 lift is 224° @ 0.050”. Both of these offer some serious potential for top-end power gains.
None of the stock LS1 cams from any vehicle have greater left than .500, and they also have intake durations below 200° and exhaust durations below 209°. A camshaft is definitely not an upgrade to be taken lightly, but if you are looking for some extra power they can perform very well.
6) ECU Tuning for the LS1
Next up for the LS1 is going to be ECU tuning. By itself, LS1 tuning will give you a healthy 10-20% power increase over your setup. In addition, while all of the above LS1 upgrades like headers and manifolds will make increased power by themselves, to really take advantage of them you’re going to want to add tuning. Tuners can optimize parameters like ignition timing, air-to-fuel ratios, and fuel pressure to get the most out of your bolt-on mods.
While tuning can help maximize your mod’s potential, it can also help them run as safely as possible, too. When you change the intake and exhaust flow on an engine, like adding an intake and headers, usually the air-to-fuel ratios change, too. While most upgrades leave the ratios in a safe area, it’s impossible to confirm that without tuning. To make sure your engine is running healthy with your mods you’ll definitely want a tuner to take a look at the car.
Best LS1 Tuners
For LS1 tuning you have a few options, they are known as either custom or canned tuning. Custom tuning is far superior to canned tuning, because it allows your tuner to customize his work to your specific engine and your specific atmospheric conditions.
Canned tunes are one-size fits all tunes that are meant to work in any environment. Custom tunes, on the other hand, provide specific adjustments for things like elevation, humidity, and air quality. Obviously, someone living in Florida and someone living in Seattle are going to have completely different atmospheric conditions. So to truly optimize your car for your mods and climate, you need to go custom.
With a custom tuner, you will need either a handheld programmer or stand-alone tuning system. Stand-alones, like an AEM EMS or Haltech ECU, will provide the most customization, but they are also the most expensive and advanced systems. Handheld programmers like the Diablo are much more user friendly, but are also limited in what they can change.
Your best option is to consult a tuner for your LS1 and then go with whichever tuning product they prefer to use.
7) LS1 Supercharger Upgrades
For our final LS1 upgrade we’re going to include superchargers. We know that most builds aren’t looking for the extreme commitment of a supercharger, but it’s definitely worth a thought. For the LS1, the most common supercharger kits involve centrifugal style superchargers. That’s not to say you can’t use others, but to fit in the engine bay, usually centrifugal kits are the best.
This is because the hood clearance for the LS1 is already pretty tight, so trying to add a huge blower to sit on-top is pretty hard. In addition, most LS1 intake manifolds are forward facing and not designed to accommodate a roots or twin-screw style of blower.
Centrifugal blowers operate a lot like turbochargers, but use a belt to drive the compressor instead of exhaust gasses. The belt drives a compressor, which compresses fresh air from the intake and feeds it through an intercooler and into the throttle body and intake manifold. Centrifugal superchargers can be mounted to the side of the manifold where there is more space.
If you’re looking to easily put your car in the 450-500 horsepower range without making intake manifold, cylinder head, or camshaft upgrades, a supercharger kit is your best option. It is honestly a much more simple upgrade than those combined and will produce more power. If you’re looking at squeezing the most power you can from the LS1 then the supercharger is the icing on the cake. However, if you’re looking for moderate street power, a supercharger with some long-tubes can prove very effective.
Best LS1 Supercharger Kits
Our recommendation for the top LS1 supercharger kits are the East Coast Supercharger C5 Corvette Supercharger Kit, and the ProCharger Kit for the Camaro, Firebird/Trans-AM, and GTO. Both kits use centrifugal style superchargers and have included intercoolers and tuning solutions.
ECS is one of the biggest names in the Corvette supercharger industry, and their C5 kits are the top of the line. They have several different options that can make anywhere from 500-1,000+ horsepower depending on blower size.
The ProCharger kits are also highly reviewed and provide excellent power and drivability. You can use whatever size ProCharger you like, but most builds like the P-1SC supercharger. It is capable of making just shy of 550 horsepower, which is great for some extra power while remaining drivable. With just 5-7 PSI of boost, the ProCharger kit can absolutely transform your LS1.
Buy Here: ProCharger for LS1 Camaro/Firebird
Top 7 LS1 Engine Mods Conclusion
The LS1 engine is a fantastic small block V8 that absolutely loves to make power. It responds incredibly well to most mods like intakes and headers, and makes great power with forced induction. The LS1 is also a very reliable engine that is known to handle some serious horsepower and torque.
We went over quite a bit in this article, covering everything from the LS1 basics to how to choose superchargers for making north of 1,000 horsepower. For most people, just an intake, set of headers, and ECU tune will prove to be the biggest bang for their buck, creating a powerful LS1 powered car with stout reliability.
For those looking at the quickest way to 600 horsepower, long-tubes and a supercharger will get you there. Big power builds looking for reliability will want to utilize all seven of our upgrades in conjunction, but that’s a pretty extreme build!
Let us know about your LS1 experiences and builds in the comments below!