LS9 Vs LS7 | in-depth comparison

There is a wide range of superpowered LS engines which have been manufactured by General Motors. The LS7 and LS9 engine are two of the most popular and advanced LS engines from General Motors.

LS9 Vs LS7

The LS9 and LS7 engine have a lot of similarities and differences between them, which makes it difficult to decide which is best for you. Below we have compared the LS9 Vs LS7 engine to help you understand the difference between the two engines.

What is the LS9 Engine?

The LS9 engine is a new engine that is the successor to the V8 engine. The V8 engine has been used in cars for many years now, and it has become a popular choice for many car manufacturers. These engines, however, have a few disadvantages. These include high emissions and fuel consumption issues.

The LS9 engine was created by General Motors as an alternative to the V8 engine. This type of engine allows for better gas mileage and lower emissions levels than the traditional V8 engines do. It also has fewer parts, so it can be built more cheaply than regular engines are made. This is al about LS9 engine. Hope you under everything about this engine. Now let’s move forward.

What is the LS7 Engine?

The LS7 engine is a 6.2L V8 engine that was produced by General Motors. It was introduced in 2005, and it is still being used today. The LS7 engine has proven to be a very powerful and reliable engine. It is widely used in many types of vehicles, including trucks, SUVs, cars, and sports cars.

The engine features an aluminum block with iron heads, which provides it with impressive durability as well as a high power-to-weight ratio.

Moreover, it features cylinder deactivation technology, which allows it to run at cruising speeds with no cylinders on board.

On top of that, this reduces emissions and improves fuel efficiency while giving power to the wheels. The engine also has variable valve timing, which allows it to be more efficient at low RPMs.

LS9 Vs LS7 Comparison

LS9 Engine LS7 Engine
Max RPM 6600 7000
Reluctor Wheel 58x 58x
Camshaft Duration 204 degree intake 211 degree intake / 230 degree exhaust
Bore X Stroke 4.125 x 3.620 inches 4.125 x 4.000 inches
Crankshaft Forged Steel Forged Steel
Compression Ratio 9.1:1 11:1
Connecting Rods Forged Titanium Forged Titanium
Cylinder Heads Roto-cast Aluminum CNC-ported Aluminum
Valves 2.16 inch titanium, intake; 1.59 inch Sodium Filled, Exhaust 2.20 inch Titanium, Intake; 1.61 inch Sodium-filled, Exhaust
Horsepower Rating 638 505
Induction Supercharged Natural Aspirated
Torque Rating 604 lb ft @ 3800 RPM 470 lb ft @ 4800 RPM
Displacement 6.2 litres 7 litres
Piston Style Flat top with valve reliefs Flat top with valve reliefs
Piston Volume +15 cc +7 cc
Exhaust Runner Volume 89 cc 86 cc
Valve Angle 12 degrees 12 degrees
Throttle Body 87 mm 90 mm, 4- bolt, Silve Blade
Fuel Injector Flow 59 lbs per hour 41.74 lbs per hour
Induction Natural Aspirate (modifieable) Natural Aspirate (modifieable)

Similarities Between LS9 Vs LS7 Engine


The first and foremost commonality between the two LS series engines is reliability. Both the engines are highly reliable as they both are manufactured under the same brand, General Motors.

Both the LS9 and LS7 engines are highly comprised of very high-quality industry-grade parts. Moreover, both the engines are light in weight and do not add much to the vehicle.

When it comes to durability, then the LS9 and LS7 series engines are made up of high-quality aluminum bodies, making them extremely durable to last longer than other standard engines.

Both the engines have sufficient horsepower along with great torque power to withstand extreme conditions.


When it comes to comparing the LS9 and LS7 engines, the design is one of the similarities. Both engines are all-aluminum, featuring a flat-top design and cylinder heads with an integrated intake manifold.

The LS9 is a small block engine that uses twin overhead camshafts and electronic fuel injection. It has a compression ratio of 9.1:1 with twin independent variable camshaft timing and individual throttle valves per cylinder actuation system on all four cylinders.

On the flip side, the LS7 is also a small block engine that uses the same twin overhead and camshafts as the LS9 engine. The LS7 engine has a compression ratio of 11:1.


The crankshaft is what turns the pistons back and forth to power the car or truck’s wheels. It can be made from any material that can withstand high heat and pressure, such as steel or aluminum.

These materials are usually coated with copper to protect them from rusting when exposed to moisture from rain, snow, or dew during cold weather conditions.

When it comes to LS9 and LS7 crankshafts, then the LS9 and LS7 are both made up of high-quality forged steel. Both the engines have industry-grade forged steel crankshaft, so you don’t have to worry about the quality at all.

Valve Angle

Valve angles of car engines are the angles between the valve seats and the cylinder bore. The angle is measured from a line that goes through both corners of the valve to the centerline of the cylinder.

The purpose of valve angles is to help reduce friction in an engine, which can be caused by improper alignment or too much wear on parts. Valve angles are also related to how well an engine runs when it’s hot, as well as how much noise it makes when it’s cold.

The valve angle of the LS9 and LS7 engines is 12 degrees, which is ideal for reducing friction.

Cylinder Heads

The term “cylinder head” refers to the part of an engine that sits above the crankshaft and contains the valves. It’s this part that houses a number of valves—hence its name, which is short for “cylindrical head.”

The material of the cylinder head is one of the most important factors to take into consideration while selecting the right engine of your choice.

The Cylinder heads of the LS9 engine are made up of Roto-cast aluminum. On the other hand, the Cylinder heads of the LS7 engine are made up of CNC-ported aluminum. Both of these are absolutely good in terms of build quality and are highly similar as well.

Reluctor Wheel

The Reluctor wheel is a component of the engine that helps in controlling the rotation speed of the crankshaft. It also helps in controlling the speed of the valves.

The reluctor wheel consists of two sets of grooved wheels, which are supported by two arms that are connected to each other by a rack and pinion mechanism.

The LS9 and LS7 engines offer a 58x Reluctor wheel which allows getting the optimum rotation speed to the crankshaft.

Difference Between LS9 Vs LS7 Engine

Supported Cars

The most common and first difference between the LS7 and LS9 engines is that they both support different models of cars. The LS7 engines are primarily designed for the Corvette or Camaro models of Chevrolet cars.

The LS7 engines have been used in different Chevrolet models. The most popular car that is equipped with the LS7 engines is Chevrolet Corvette Z06 and Camarao Z/28.

On the other side, the LS9 engine is also used in many car models of Chevrolet. For instance, the Corvette ZR1, HSV GTSR W1, and Equus Bass 770 are all equipped with LS9 engines.


Performance is what matters the most when comparing automobile engines. Both the LS9 and LS7 engines offer great performance and more than enough power output.

The LS7 has a displacement of 7 liters, while the LS9 has a displacement of about 6.2 liters. The LS9 offers a 683 horsepower rating in comparison to the 505 horsepower rating of the LS7 series engines.

The LS9 engines are quite powerful as they offer a torque rating of 604 lb-ft @ 3800 RPM in comparison to the LS7 series torque rating of 470 lb-ft @ 4800 RPM.

The best part about these two LS series engines is that you can increase their performance with some modifications.

You can not only increase the performance by also boosting the horsepower and making them extremely powerful and high-performance engines.


Another essential consideration when selecting LS engines is acceleration. The rate of increase in velocity per unit of time is known as acceleration.

The difference between the LS9 and LS7 engines is in their acceleration. Both engines can accelerate to a very high speed within a couple of seconds. Moreover, these engines can easily reach the top speed within a glance.

To be precise, the LS9 engines have better acceleration than the LS7 engines. This is due to the fact that they are newer engines in comparison to the LS7 engines.

Moreover, the LS7 engines have a greater horsepower along with a better torque rating, which helps them achieve greater acceleration within some time.

Within 11.3 seconds, the LS9 engines can produce the ZR1 to ¼ mile times. Also, the LS9 engine comes with the ZR1 posts 0 to 60 MPH times of only 3.4 seconds and 0 to 100 MPH times of 7 seconds.

On top of that, the LS9 engine can get up to 0 to 60 MPH within 3.7 seconds. Not just that, the LS9 engine also offers a top speed of about 198 mph.

On the other hand, the LS7 engine gives comparable performance from 0 to 60 MPH in 3.7 seconds, quarter-mile speeds of 11.7 seconds at 127 MPH, and a top speed of roughly 198 MPH.


RPM stands for revolution per minute, and it signifies the speed of the engines. RPM is another great difference between the LS9 and LS7 engines. Both engines operate at different RPMs.

Though the difference is not big, it may matter for some users based on their individual preferences. The LS7 engines operate at an RPM rate of about 7000 at maximum.

On the other hand, the LS9 engine offers an RPM value of about 6600 at max. RPM can signify a lot of things about these two engines. However, you should not make your decision based on RPM because RPM cannot tell you about the power generated by an engine.

The LS7 engine has higher RPM due to the fact that the LS7 engine comes with a bigger displacement cylinder which allows them to generate more RPM in comparison to the LS9 series engines.

Fuel Injector Flow

The fuel injector is the part of the engine that delivers fuel to the combustion chamber. The fuel injector has an atomizing nozzle at its tip, which sprays a precise volume of gas and fuel into the combustion chamber.

The amount of gas delivered by a given nozzle depends on factors such as speed, pressure, temperature, and others. Fuel injectors are located in the intake tract of most engines, allowing them to deliver fuel directly into the combustion chamber.

The more fuel the injector will flow, the more power will be generated by the engines. It is as simple as that.

When it comes to the better fuel injector flow, then the LS9 is the ultimate winner due to its greater fuel injector, which can flow fuel at higher speeds than the LS7 engines. Thus, the LS9 series engines generate more power by burning more fuel.

Read: 5w40 vs 10w30

Fuel Efficiency

The fuel injector is directly responsible for the fuel efficiency in any engine. The more fuel the injector will flow, the lesser will the fuel efficiency of the engine.

And since the LS9 engines have a higher fuel injector flow, they have low fuel efficiency. The fuel efficiency is another major difference between the LS9 and LS7 series engines.

If you are someone, who likes to prefer better fuel economy over power, then you should go with the LS7 series engines. On the other side, if you like to prefer power over fuel efficiency, then the LS9 series engines are the ideal choice for you.

The LS7 series engines offer an average mileage of about 30 to 31 MPG. On the other hand, the LS9 engine offers a very low average mileage of about 22 MPG, which is low due to its higher fuel injection rate.

However, one should note that the LS9 engines offer a lot more power for the built-in supercharging capabilities, allowing you to ride in extreme road conditions.


Pricing or the cost is another important factor when choosing the right engine for your car. Some people prefer pocket management, while others prefer to have better things. Whatever you decide, in the end, it all depends upon your budget and needs.

The LS9 and LS7 are both high-end engines, so you will have to pay a premium for both these engines. The LS9, on the other hand, is slightly more expensive in comparison to the LS7 engines.

The LS7 series engines cost anywhere from $15,000 to $17,000. On the other side, the LS9 engines cost a lot more, anywhere between $21,000 or above, which is a lot more than the LS7 series engines.

Pros and Cons of LS9 Vs LS7

LS9 Engines:

Pros Cons
Better power High pricing
Great acceleration
Higher fuel injection
Excellent performance

LS7 Engines:

Pros Cons
Affordable pricing Average acceleration
Great fuel economy Less fuel injection
High RPM
Decent performance

Which is Better: LS9 Vs LS7?

The LS9 and LS7 both are highly functional engines with modern technology offered by General Motors. Depending upon your personal preferences, you can choose the right engine.

For instance, the LS9 engine offers great performance, better acceleration, greater horsepower along with torque, and many other eye-catching features.

On the other hand, the LS7 offers a greater fuel economy, affordable pricing, and higher RPM power. But when it comes to choosing the best, then the LS9 engine is our pick. You can go with this without any doubt.

Frequently Asked Questions:

Can you increase horsepower in the LS7 engine?

Yes, you can increase horsepower in LS7 engines. You will have to make some modifications to increase the performance. Moreover, you can also increase the horsepower in the LS9 engine with some basic modifications.

How much horsepower can an LS9 engine handle?

An LS9 engine can easily handle up to 1,000 Horsepower. However, the engine will only be able to handle such high horsepower in extreme high cylinder pressure.

Can the LS7 engines be Supercharged?

Normally, you cannot easily supercharge the LS7 engines. They will need a high amount of modification which can only be done by professionals and experts. However, we don’t recommend supercharging LS7 engines.

How much power will the supercharged LS7 be able to handle?

Well, it depends on how much the engine has been supercharged. Generally, the supercharged engines can handle up to 600 horsepower. However, in some cases, the horsepower can go very high.


In the end, it all boils down to your own personal preferences, budget, and requirements. If you like to have a powerful engine that offers superior performance, then you can go with the LS9 engine.

However, if you like to go with an affordable engine that offers better fuel economy, then the LS7 is a better choice. Ultimately, it all depends upon you, which engine fits your budget and needs. This is all about the LS9 Vs LS7 engine hope with the help of this wonderful article we have cleared all the doubts regarding these two LS9 Vs LS7 engines.

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