With emissions getting more stringent, large displacement naturally-aspirated engines are becoming a thing of the past. Manufacturers are having trouble getting these engines to meet regulations and are actively sizing down. Forced induction has fully replaced displacement, and there are no signs of that changing in the near future, or ever.
When you think of large displacement engines, you think of big ole American V8s like the LS engines. The long-lasting LS range had numerous – if not all – large-displacement options. The biggest of the already-big LS models is the LS7 engine. And how big is that? The LS7 engine is a 7.0-liter (or 427.8 cu in) engine. This engine was also one of the final LS offerings, and it was based on the Gen 4 architecture.
In this short guide, we’ll revisit this engine and discuss what it’s like and what made it so special. Our goal is to figure out whether this is the best LS ever made?
LS7 Engine Specs
When Chevrolet introduced the LS7 engine, it brought a lot of changes compared to the LS designs that came before it. The engine features a different block and sleeved cylinders. The way this engine achieves its size is down to a larger bore and longer stroke.
The bore was pushed to 4.125 inches, while the stroke reached 4 inches. General Motors also made other changes like adding a forged steel crankshaft and main bearings. You could also find titanium connecting rods and hypereutectic pistons in these. After all, this motor was putting down big power. It was only logical to make sure that the internals could handle it.
The LS7 engine put out 505 HP at 6,300 RPM and 470 lb-ft at 4,800 RPM in stock form. All that with a redline at 7,000 RPM, mind you. Even so, GM has left at least 1,000 RPM on the table as some of these motors were repeatedly pushed to 8,000 RPM with little to no issues. Of course, that would be playing with fire for most owners.
While the company pushed limits during testing, they refrained from taking it to that level in production form. This was done to keep the camshaft’s hydraulic lifters safe and ensure that the engine was getting the air it needed. Each LS7 engine was hand-built at the General Motors Performance Build Center.
What Car Has an LS7 Engine?
The LS7 engine powered the Chevrolet Corvette Z06 from 2006 to 2013. It was in this car that this engine gained its popularity. However, the Corvette wasn’t the only car to get a massive power plant. The 2014 and 2015 Chevrolet Camaro Z28 also made use of this engine. While those two car models were the only ones to get the 427 LS7 from the factory, General Motors sold the LS7 as a crate engine.
General Motors’ Australian division Holden also made use of the new LS. Holden Special Vehicles came with the LS7 in a special edition model called the W427. In this application, the LS7 made 503 HP at 6,500 RPM and 472 lb-ft at 5,000 RPM.
That said, it wasn’t the first Australian car to come equipped with this engine. Before the W427, It was the Holden CSV GTS that first introduced the 7-liter monster down under. The company also claimed that it was tuned to make 536 HP and 443 lb-ft in this car.
What Makes the LS7 Engine So Good?
When the LS7 engine made its debut under the hood of the Corvette Z06, it made it the most powerful Corvette ever. People liked the fact that it was a 7.0-liter or 427 cubic inches, as that matched the displacement of the original Corvette from the 1960s. Sentimental symbology aside, the engines in the older car used a big block, while the LS7 engine had a small block.
The LS7 was admired because it produced big block levels of torque in a small block package. That meant a better power to weight ratio as it was light, compact, and considerably more efficient than the original 427s.
Aside from the titanium bits we’ve mentioned before, there isn’t a lot on the parts list that hints at the immense capability of this engine. It’s still the same small block pushrod setup, but this time around with more displacement, but also better airflow. If you look closely though, you’ll notice that this engine features rectangular intake ports, which were first introduced on the LS2.
However, the ones on the LS7 head sport a different, less obstructive profile. Something else that stands out is how the LS7 engine revs. Despite being a massive 7.0-liter unit, the engine revs to 7,000 RPM with almost no effort.
It doesn’t just rev high and quick, but also makes its peak power at 6,300 RPM. That’s extremely impressive for a 7.0-liter engine that uses a push-rod configuration. That’s not all, the way it delivers its torque is rather impressive as well. Its torque curve is flat, making the tremendous 400 lb-ft available all the way from 2,400 RPM to6,400 RPM.
The Chevrolet Corvette Z06 came equipped with independent cooling systems for its oil, power steering, transmission, and rear axle. What this means is that these systems weren’t dependent on the LS7 engine, allowing it to work at its full potential.
Back in 2006, Motortrend tested the car at the General Motors Milford Proving Ground and got some impressive results. The LS7 engine-equipped Corvette reached 60 MPH in just 3.5 seconds and did the quarter-mile in 11.5 seconds. Those numbers surpassed the Porsche 911 Turbo and Ferrari F430 at the time while costing significantly less.
This is rather impressive when you factor in that the Z06 weighs 3147 lbs. Motortrend also called the 7,000 RPM redline superfluous and described the torque as “weapons-grade”. They went on to say that the torque delivery was rich and flat and that 3rd gear is all you need in most situations. Such a strong performance profile has allowed it to gap the likes of the BMW E60 M5 and other big names of the era.
When Car and Driver got their hands on the 2014 Chevrolet Camaro Z28, they said that the LS7 engine oozes power while it was standing still or at speed. The engine would race towards its redline while delivering an impressive exhaust note. The Camaro was considerably heavier than the Corvette which meant it took 4.4 seconds to get to 60 MPH. The quarter-mile, meanwhile, was achieved in 12.7 seconds.
Can the LS7 Engine Be Modified?
The LS7 engine makes a substantial amount of power and torque right out of the box, but if for some reason that’s not sufficient it can be modified to make more… a lot more. Even the bolt-ons will put you in dangerous territory with this motor.
Bolt-on mods for this motor include a cold air intake and a less restrictive exhaust. Slap a good tune on that setup, and you’re talking 500ish HP at the wheels.
You can go one step further in the NA direction. For example, an aftermarket cylinder head, a performance valvetrain, throttle body, and an aftermarket manifold can add more power to the equation, a lot more power.
While the LS7 engine has cylinder heads that work well with modifications, there have been instances where the flow on the exhaust side has proved to be a problem. Nonetheless, these heads can be ported to improve airflow. The LS7 engine also handles a camshaft swap quite well, like most LS engines. When paired with the supporting modifications, this will result in a noticeable performance gain.
Many LS7 engine owners decide to go down the forced induction route and use superchargers. This can be either a roots style or a centrifugal style unit. With this modification, the engine can gain around 150 HP quite easily. However, if you are looking to take the power figure above the 700 HP mark, you will have to pull the motor apart and upgrade the internals. Needless to say, every time forced induction is used, you are also looking at higher-flowing injectors and fuel pumps among other mods.
The most important thing is that an average LS7 gives you plenty of options when it comes to extracting more power. No matter which route you go, there will plenty of bolt-ons, proven setups, complete upgrade kits and most importantly — massive communities of experienced enthusiasts willing to lend a helping hand.
What Is the LS7 Valve Issue?
The LS7 engine is known to be quite reliable, even after owners push it to its limits. However, there has been one major problem that it suffered, and it has to do with its valves. General Motors released a statement that said the problem was traced back to the supplier of its cylinder heads. They managed to figure this out by studying the heads returned under warranty.
The problem occurred simply because some heads weren’t machined correctly. As a result, the valve guides and valve seats weren’t concentric, and that caused major damage to the valve guides. The LS7 engine valve issue isn’t as major as the news articles online would lead you to believe. General Motors believes that only 10 percent of the Corvette Z06s are affected – that’s a total of 1300 units.
Is the LS7 Discontinued?
Yes, the LS7 engine has been discontinued, but it happened a lot more recently than you would think. While it was used in General Motors’ vehicles quite a few years ago, the company continued to offer it as a crate motor. The crate motor was sold by Chevrolet Performance but ended up being discontinued earlier this year (2022).
The company first shared that it was considering discontinuing the race-bred engine in June 2020. At the time, it was believed that the newer LS427/570 would be kept around as an alternative. However, both versions ended up on the chopping block.
General Motors also stopped offering its most powerful engine ever – the LT5 – after keeping it around for only a year. The company didn’t share the exact reason for the discontinuation of these engines, but we believe strict emission norms may have played a role.
Not all is lost, though. There are still plenty of LS7 that can be obtained brand new, or with various modifications. What it comes down to is your budget and the power level you are looking at. However, the LS7 engine is one of the best LS engines made, making them quite expensive. Prices range from $9000-25000.
Maintaining the LS7 Engine
As you might expect, a high-performance engine like the LS7 requires its fair share of maintenance. That being said, it’s not an overly complicated engine and most maintenance is quite straightforward with the right parts. That’s where we come in! Newparts.com offers a massive catalog that includes genuine, OEM and aftermarket parts for most GM products.
If you’re looking for quality, you’re in the right place! Simply select your vehicle using our vehicle selection tool, and we’ll show you parts that are a guaranteed fit for your car!
