LS3 Vs LS7 Heads – 12 Differences Everyone Must Know About!

Written By: Terrence Hines
Category: Engine

When looking to up your vehicle’s performance, deciding between LS3 vs. LS7 heads can be a daunting task that many find difficult to navigate.

You can use either option to increase power without spending too much. Thus, we will share some differences today to help you make a wise decision.

LS3 Vs. LS7 Heads – 12 Differences

LS3 and LS7 heads are cylinder heads typically found in certain high-performance vehicles.

These heads feature improved flow characteristics over traditional cylinder heads, which allow them to produce more power when paired with other performance parts.

Additionally, they help reduce weight, making them ideal for race cars or performance street cars.

Whether you are constructing your dream engine or simply looking to enhance power and reliability, the LS3/LS7 heads are an ideal choice.

Boasting high horsepower output capabilities, these engines will provide superior performance for any LS-powered build!

Understanding the discrepancies between the two will assist you in determining the ideal head for your engine.

1. LS3 Heads Are Less Expensive Than LS7 Heads:

LS3 heads are great cost-effective engine parts that can be easily swapped out in cars to increase performance.

LS3 heads offer more power than LS1, LS2, and LS6 heads and are cheaper than LS7 heads.

LS3 Vs. LS7 Heads - 12 Differences

The LS3 heads can provide more horsepower than the LS7s and cost less. Additionally, the LS3 heads have better flow per gram of air charge while having smaller components.

For those looking to upgrade their car’s engine without breaking the bank, LS3 heads are a great option that won’t sacrifice power for affordability.

2. LS3 Heads Offer More Torque Than LS7 Heads:

LS3 heads are a great option for any engine builder looking to boost their LS-based engine’s torque.

They offer superior performance and power output compared to LS7 heads, thanks to their improved intake, exhaust runner port designs, and larger valve sizes.

LS3 heads include larger 2.165-inch diameter intake valves, as well as 1.59-inch diameter exhaust valves, giving LS engines great breathing capacity for added power and performance.

This helps LS-based engines get the most out of their air/fuel mixture during combustion, allowing them to unleash more torque when compared to LS7 heads.

3. LS3 Heads Flow Better At High Rpms Than LS7 Heads:

LS3 heads offer higher output at high RPMs than LS7 heads, making them a popular choice for car enthusiasts looking to optimize their engine’s performance.

LS3 engines can be efficiently used for drag racing, road racing, and drifting due to their excellent flow rates when running at higher revs.

LS3 Heads Flow Better At High Rpms Than LS7 Heads

LS7 heads are better for uses that don’t go fast, like driving around town or off-roading. LS3 heads are better for uses that go faster or that last longer.

Ultimately, the selection of LS3 or LS7 heads should be tailored to individual needs and preferences.

4. LS7 Heads Have A Larger Chamber Volume Than LS3 Heads:

LS7 heads offer an advantage over LS3 heads due to their larger chamber volume.

This additional chamber space helps to create a smoother airflow that contributes to increased horsepower and better combustion.

The LS7 heads are advanced in design, providing a larger intake port for greater air ingestion during combustion and leading to increased power.

Additionally, LS7 heads feature exhaust ports with improved angles and diameters, allowing for further power increases.

In comparison, LS3 heads offer smaller intake and exhaust ports with less efficient angles and diameters, compromising airflow that limits engine output performance.

5. The Valve Angles In The LS7 Head Are Different From The Valve Angles In The LS3 Head:

LS7 cylinder heads are distinctive from LS3 models in that the valves have a distinct tilt.

Referred to as “LS-Revolution angle,” these LS7 heads have valve angles adjusted from 15 degrees on LS3 engines to advanced 12-degree angles.

This particular valve angle significantly impacts how it handles engine performance and increases exhaust flow, resulting in better power output and higher rev range capabilities.

The LS7 engine is designed for swiftness and performance, making it exceptionally powerful. This allows the engine to accelerate quicker than its counterparts.

6. The Intake Ports In The LS7 Head Are Bigger Than The Intake Ports In The LS3 Head:

LS3 vs. LS7 heads are a common topic amongst auto enthusiasts because the LS3 head and LS7 head are two of the most popular cylinder heads on the market today.

The LS7 head was designed to create more power than its LS3 counterpart, with specs that include larger intake ports.

LS3 Vs. LS7 Heads

The LS7 intake ports stand 12mm taller than the ports on the LS3 head, allowing it to gulp more air with each passing second.

The LS7 is more powerful and popular because it has larger intake ports. This means it can produce better horsepower numbers with just a little tuning or special equipment.

7. The LS7 Head Is Made Of Aluminum, While The LS3 Head Is Made Of Cast Iron:

LS3 and LS7 engine heads are integral to modern engines, but the major difference lies in their construction materials.

The LS7 head is made from aluminum, while the LS3 head is made from cast iron.

The aluminum LS7 head is a better choice than the LS3 iron head because it is lighter and therefore puts less strain on the engine, which improves gas mileage.

The aluminum LS7 head also does a better job rejecting heat than the iron LS3 head.

Additionally, aluminum LS7 heads have finer port detailing, allowing for improved engine performances for higher power output.

8. The LS7 Heads Have Larger Valves Than LS3 Heads:

The LS7 heads have larger valves than LS3 heads, making them more efficient in the combustion cycle.

This upgrade allows for a seamless fuel transfer from the intake to the cylinder while increasing airflow.

LS7 heads are great for those looking to get the maximum performance out of their vehicle engine, as they help extract greater torque and horsepower.

Plus, LS7s offer improved cooling capabilities that support long-term reliability and endurance.

LS3s still offer superior performance compared to non-upgraded engines, but if you’re looking for that extra oomph in your ride LS7 is the way to go!

9. The LS7 Heads Feature Unique Valve Springs That Are Not Found In LS3 Heads:

LS3 and LS7 heads are two of the most powerful engine heads that GM has produced, but the LS7s have an advantage that LS3s don’t: LS7 valve springs.

LS7 valve springs are designed to handle higher lift camshafts and larger valves than LS3 springs can, allowing LS7 engines to make more horsepower and torque.

Additionally, LS7’s beehive-style valve springs produce fewer harmonic frequencies when under extreme shocks, providing a smoother ride for drivers.

If you’re looking for more power out of your engine, look no further than LS7 heads – they feature unique valve springs that give them the edge over LS3 heads.

10. The LS7 Head Has Improved Combustion, Which Increases Power Output:

LS7 heads are a great way to upgrade your LS3 engine and increase power output.

LS3 heads come standard on LS3 engines and have improved combustion chambers, intake ports, and exhaust manifolds than LS1-LS6 heads.

The LS7 cylinder head was constructed with more effective ports and chamber shapes and an improved valvetrain design allowing superior air intake to improve combustion.

This gives the LS7 head a distinct advantage over LS3 or other LSX Series Heads by increasing power output by up to 30hp.

The LS7 Head Has Improved Combustion, Which Increases Power Output

So, if you’re looking for a quick and easy way to improve your LS3 engine’s performance, the LS7 head is the way to go.

11. The LS7 Head Features Improved Port Shapes And Larger Valves, Which Can Increase Air Flow:

LS7 heads boast an important advantage over LS3 regarding air intake.

Their improved port shapes, along with larger valves, grant greater airflow into the combustion chamber; this allows for substantially more power generated per stroke of the engine!

This increased performance does come at a price, however; LS7 heads are typically more expensive than LS3 heads due to the engineering feat needed for their manufacture.

Those looking to take their engine performance to the next level would do well to invest in LS7 heads, as it could be a game changer for them.

12. The LS7 Head Also Has A Higher Compression Ratio Than LS3 Heads:

The LS3 and LS7 heads are different in how they work. The LS3 has a large intake port, which is good for power and torque levels. The LS7 heads are different in this regard.

LS7 heads feature larger intake components compared to LS3 heads which results in a higher compression ratio.

This higher compression ratio allows LS7 head engines to reach new heights with their engine power and torque, giving drivers access to more performance under the hood.

As such, engine experts often look to LS7 heads when they want to upgrade an LS-based engine or get more from it.


LS3 and LS7 heads are reliable performance equipment that can help any engine reach its full potential.

LS3 heads are ideal for vehicles looking for improved torque and fuel economy, while LS7 heads offer increased power and rpm capabilities.

Depending on your desired results and budget, it is essential to weigh the varying costs of each option before making a decision.

LS3 vs. LS7 heads are the perfect example of choosing the best piece of performance equipment possible for an engine’s specific needs.

Terrence Hines

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