LS7 vs LS3 Engines: How The Small Block V8 Models Compare

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LS7 vs LS3 engines are one of the things that most car owners are confused about, because both are small block V8 engines with some similarities. If you are driving a GM or Chevy vehicle, you might need a small block, but choosing between these two is not a piece of cake.

LS7 vs LS3 Engines

Although both engines are small block models from GM that belong to the 4th generation, there are some important differences between them. If you’re wondering what to choose between these two engines, our guide below covers all you need to know.

Features LS7 LS3
Production Year 2006-2015 2008-2017
Cylinder Bore Size 104.8mm 103.25mm
Piston Stoke Size 101.6mm 92mm
Displacement  7008 cc 6162 cc
Material  Cast aluminum  Cast aluminum 


What Is the Main Difference Between LS7 and LS3 Engines?

The main difference between LS7 and LS3 engines is that the LS7 engine provides more horsepower, set at 505, while the LS3 engine has less power, from 426 to 436 horsepower. Another notable difference is that the displacement of the LS7 is 7.0L while the LS3 is 6.2L.

The LS7 engine is highly reliable, but this also makes it more expensive than the LS3 engine. The engines in the LS series are the most recognized of these small block engines as they offer accessibility, durability and versatility. The LS in LS3 means luxury sport. The car engine is majorly used in expensive cars that provide top performance, like the Chevrolet series.

The most popular engines in the series are the LS3 and the LS7, and while the LS7 engine is the older model, both have some similarities. For instance, they are both made from cast aluminum and have sequential fuel injection systems.

– Comparing the LS7 and LS3 Engines

Here is a detailed list of the differences between the LS3 and LS7 engines.

  • The LS7 is an older engine model that was produced from 2006 to 2015, while the LS3 was produced from 2008 to 2017. You can buy these engines as a remanufactured option.
  • The LS7 engine is meant to fit the Camaro X28 and Corvette Z06 engines, with a displacement of 7008 cc or 427.6 cubic inches. But, the LS3 engine is designed to fit the G8 GXP, Chevy Corvette and Camaro SS with a displacement measuring 6162 cc or 376.0 cubic inches.
  • The LS7 engine has more torque, rated at 470 pound-feet at 4800 RPM, while the LS3 has torque from 420 to 428 lb-ft at 4600 RPM. As for the horsepower, it is 505 and 426-436, respectively.
  • Another difference is the compression ratio, which is 10.7:1 for the LS3 and 11.0:1 for the LS7. This makes the LS3 more fuel efficient.
  • The LS7 engine costs almost double the price of the LS3 engine.

– Specifications and Features of LS7 Engines

LS7 engine is a GM engine that was released in 2006 and is built from cast steel and aluminum. The engine contains a light block and provides top-notch durability. The engine contains 474 lb-ft of torque and gives out 505 horsepower. The design of the LS7 engine comes with a race-derived cylinder head, which provides maximum airflow.

Characteristics and Specifications of LS7 Engine

The engine contains exhaust and intake outlets which are computer controlled, and come with 70cc combustion chambers. The airflow restrictions are removed to improve the power. It has a high-flow intake manifold that matches its cylinder head.

It also comes with an acoustic shell and foam that has been fitted to the intake manifold to block out any unwanted noise. The engine has a dry-sump system too, which allows for efficient oil consumption.

– Specifications

Here are the specifications of the LS7 engine:

  • Part number: 19329246
  • Displacement: 427 cu. in. (7.0L)
  • Crankshaft: Forged steel
  • Piston: Hypereutectic aluminum
  • Camshaft Type: Hydraulic roller
  • Camshaft duration: 211 degrees intake / 230 degrees exhaust
  • Compression ratio: 11.0:1
  • Horsepower: 505
  • Bore x Stroke: 4.125 x 4.000 inches
  • Block: Cast aluminum
  • Connecting rods: Forged titanium
  • Valve lift in inches: .593 intake / .588 exhaust
  • Valve size in inches: 2.200 intake / 1.610 exhaust
  • Max recommended RPM: 7000

– Special Features

The LS7 engine comes with a couple of enhancements that make it better than some other models in the series. This makes it powerful, especially with the increase in power output that makes it better at high engine speeds.

Some of the features that make the LS7 engine special include the following:

  • It has a higher compression ratio.
  • It features a large cylinder bore.
  • There is superior airflow through the heads.

The LS7 can be found in different GM cars, including the Chevrolet Corvette Z06 and as a crate engine from GM Performance.

– Reliability of the Engine

The LS7 engine is more reliable than the LS3 due to its performance level, but this does not mean that it is perfect. There are some problems with the engine, especially in the exhaust valves and oil system, but it is easy to upgrade the engine if you want to solve the problem.

The main problems of the engine include leaking or burning oil, a knocking noise in the engine, and oil pressure issues. Some users have complained that the exhaust valve is getting separated from the stem. There is also cavitation in the oil system.

The LS7 also has poor fuel economy because of all the power that it requires to function.

– Pros of Using This Engine

The main benefit of the LS7 engine is the construction, as it is light and durable since it’s made from aluminum. This causes it to last for a long time. The engine has a high-performance level of up to 505 horsepower, which makes it ideal for power vehicles.

It comes with a 58X ignition system, which allows for precise ignition timing. This leads to a decent fuel economy and enhanced performance. If you want to maintain or repair the LS7 engine, it is easy since the parts are easy to come by.

– Cons of Using This Engine

The main downside of the LS7 engine is the oil system, which has cavitation issues. But you can replace this part with a better model to improve the oil supply. Also, the fuel economy is pretty bad, but you get good performance instead.

– Ideal Consumer

The engine is ideal for you if you want a powerful engine that can handle high performance and speed in driving. In general, it depends on your budget and what you will use the car for. If your car will be used for sports and racing, the engine is an ideal choice.

The LS7 is also a good choice if you want to make a project car since it has a higher redline and produces more power. It is more reliable and durable when working on a project car. But, if you’re concerned about the price, the LS7 is not suitable since it is expensive.

– Specifications and Features of LS3 Engines

The LS3 engine is a 4th-generation small block engine that was first manufactured in 2008 and inserted in Corvettes. It is one of the LS engines for Chevy supercars due to its performance. The LS3 engine features a sequential fuel injection system and a 6.2-litre displacement.

Specifications and Features of LS3 Engine

When the engine was first released, it had 430 horsepower, but then it was customized to have 436 horsepower instead. It has always featured 424 pound-feet of torque. In this V8 engine, you will notice high-flow cylinder heads, which allow for adequate airflow.

The engine is also designed with a high-flow intake manifold to fit the cylinder heads and a 58x ignition unit for good timing. The motor is manufactured with a crankshaft ring and sensor for an accurate reading.

– Specifications

Here are the specs that you should expect from the LS3 engine:

  • Part number 19369326
  • Displacement: 376 cu. in. (6.2L)
  • Crankshaft: Nodular iron
  • Piston: Hypereutectic aluminum
  • Camshaft Type: Hydraulic roller
  • Camshaft duration: 204 degrees intake / 211 degrees exhaust
  • Compression ratio: 10.7:1
  • Horsepower: 436
  • Bore x Stroke: 4.065 x 3.622 inches
  • Block: Cast aluminum
  • Connecting rods: Powdered metal
  • Valve Lift in inches: .551 intake / .552 exhaust
  • Valve size in inches: 2.165 intake / 1.590 exhaust
  • Max recommended RPM: 6600

– Special Features

The LS3 engine has some features that make it efficient and powerful. The engine offers an increase in power output, going up to 430 hp and has a higher redline at 6500 rpm. This gives it better power at high engine speeds.

What makes the LS3 engine special is:

  • There is an improved airflow through the heads.
  • There is a larger cylinder bore.
  • It has an aggressive camshaft profile.

The LS3 can be found in different GM cars, including Pontiac G8 GXP, Chevrolet Camaro, and Chevrolet Corvette. It is also a crate engine.

– Reliability of the Engine

The LS3 comes with more issues than the LS7, with the main problem being the faulty rings. This can cause more oil consumption. Other common problems of the engine include burning or leaking oil and problems with the oil pressure.

Also, as the LS3 engine wears out, the mileage racks up. This is bad because it wears out pretty quickly. You might have to replace the valve and lifter more often.

– Pros of Using This Engine

The main advantage of the LS3 engine is the horsepower it has. It offers 430 hp before boosting. Despite its compact size, it is robust, and this makes it ideal for power and muscle cars.

The engine also has a strong aluminum build, which makes it light and durable. Other parts of the engine are made with steel for better durability. Its small stature makes it ideal for fitting in vehicles, and it has good fuel economy.

– Cons of Using This Engine

The main downside of the LS3 engine is its small size, which makes it harder to maintain. If you want to replace a part like a lifter, you have to extract the whole engine. Also, it commonly has problems with the piston ring, which leads to high oil consumption or engine blow-by.

– Ideal Consumer

This engine is ideal for you if you want a model that provides affordability along with top-notch power and performance. It’s a great engine with more value for your money, so consider it if you want an LS engine on a budget.

Frequently Asked Question

– Which LS Engine Is Considered the Strongest?

The LS engine that is considered the strongest is the LS9. This is the most powerful engine and the first one in the series to get a supercharger. It features 376 ci and 6.2 liters, while the horsepower is 638.

How Does the Power Output of the LS7 Engine Compare to the LS3 Engine?

The comparison of power measurements between the LS7 and LS3 engines reveals intriguing differences. When it comes to pure power, the LS7 engine outshines the LS3. With its larger displacement, aggressive camshaft, and improved airflow characteristics, the LS7 generates an impressive 505 horsepower and 470 lb-ft of torque. In contrast, the LS3 engine offers a still-impressive 430 horsepower and 424 lb-ft of torque. The LS7’s higher power output makes it a preferred choice for those seeking blistering performance and exhilarating acceleration.


When comparing the LS7 vs LS3 engines, it’s important to consider which one is ideal for you based on your needs and the type of car you’re driving.

Here’s a summary of our article in a quick and handy list for your perusal:

  • The main difference between the LS3 and LS7 engines is that the latter is more powerful and has a displacement of 7.0L.
  • The LS7 engine was released in 2006 with a horsepower of 505 and 474 pound-feet of torque.
  • The LS7 engine is highly reliable but has poor fuel economy.
  • The LS3 engine was first manufactured in 2008 with horsepower between 430 and 436 and a torque of 424 pound-feet.
  • The LS3 engine is highly affordable with good fuel economy.

The LS7 and LS3 engines are both high-quality models from GM that can be used in high-end cars. Consider their cost and performance and select the best one for your vehicle and budget.


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