The LS family is a series of engines that are actually really similar to each other. The architect of the Gen III and Gen IV Chevy V8’s is extremely similar. The Gen IV’s are supposed to have a slightly stronger block, but not by much.
The main difference between the engines in the LS family is the displacement, intake, camshaft, and various small details. The LS2 and the LS3 have a lot in common. But, the most obvious difference between the two is the displacement.
The LS2 has 6.0L of displacement, and is technically was the first Gen IV Chevrolet engine. The LS3, on the other hand, has 6.2L of displacement and is also Gen IV Chevrolet engine.
But I’m sure you’re wondering if there are other things that are different between these two, other than the displacement. So, let’s dive in, and compare LS2 vs LS3.
LS2 vs LS3: Cylinder Heads
One of the biggest horsepower gains most V8’s have is with aftermarket cylinder heads. Luckily GM was actually really good at developing cylinder heads when they designed the LS engine.
Throughout the years Chevrolet continued to perfect the LS heads. The LS2 heads were a slight step up from the LS1 heads.
To no one’s surprise, the LS3 heads are better than the LS2 heads. I am unable to find definitive flow numbers for both heads.
But, from browsing around forums and asking some engine builders, it seems like bolting LS3 heads onto an LS2 will gain you about 20whp+. A 20whp gain is pretty impressive considering your swapping OEM parts with more OEM parts.
These gains are due to changes in the intake runner length, size, and shape. Small things like shape can have a large effect on how air flows into the engine.
LS2 vs LS3: Intake
Just like the LS1 vs LS2 debate, the later engine has a slightly better intake manifold. This is the case from the LS2 vs LS3 debate.
Chevrolet increased the intake manifold flow by straightening out the intake runner and optimizing the flow path from the intake manifold to the cylinder heads.
This all adds up to a slightly better intake manifold. The manifold’s increased flow helps bump the power up about 5 horsepower compared to the LS2’s intake manifold.
LS2 vs LS3: Displacement
We briefly covered the difference in displacement at the beginning on this article. The LS2 has 6.0L of displacement, whilst the LS3 has 6.2L of displacement. But, the has the same exact amount of stroke.
Their bottom end is actually near identical, but the Chevy gave the LS3 an extra 12 cubic inches of displacement. “How?” you might ask.
Chevrolet upped the displacement of the LS3 by giving it a slightly larger bore. The LS2 has a bore of 101.6, whilst the LS3 has a bore of 103.25mm.
As I mentioned before, this gives the LS3 an extra 12 cubic inches (.2L) of displacement. This helped up the horsepower from 400 to 430.
The increased bore also helps make the LS3 much happier to revs. It revs up much quicker than the LS2 and generally responds quicker to throttle inputs. The increased bore also means slightly higher RPM potential.
The increased potential for RPM’s makes the LS3 a favorite amongst high-performance engine builders.
LS2 vs LS3: Cost
When you think of picking up a used LS engine, most people think of either an LS1 from a Camaro or an LM7 from a Tahoe. Why is this? Because both those engines are pretty old and pretty abundant.
Both of these things make them dirt cheap. But what about the later LS engines like the LS2 and LS3?
The LS2 was released in 2005. It was the new Corvette base engine, as well as an optional engine from the 05-06 GTO.
Because of its smaller production, and the fact that it’s newer, the LS2 is typically much more expensive than an LS1, but isn’t really worth the premium to most enthusiasts.
The LS3 was released in 2008. Much like the LS2 before it, it was the all-new base Corvette engine.
The LS3 was also used in the 2010 to 2015 Camaro. This means that the LS3 is much more abundant than the LS2. But, because of how new the engine is, they’re still fairly expensive.
So yes, the LS2 is cheaper, but not by a huge amount. Honestly, for how much better the LS3 is I would personally just save up for a little longer and go with an LS3 instead.
The ls2 was the only engine available on 05-06 GTO’s
So, what are you saying? I’m not understanding.
The article says optional.
I dyno tested LS engines when I worked for GM. Bottom line is you can beat the snot out of an LS2 for 72 hours, and it makes more HP, more TQ, less crankcase pressure and less blowby as the test proceeds. You can literally compare run data from 1 hour into test against data 2 hours into the test and see an improvement. Likewise between hour 72 and hour 71. Conversely, the LS3 would snatch a wristpin out of a piston ~23-25 hours into the same test. LS2 is far superior based on my direct experience testing both.
And GM’s engine dynos also showed LS2 making more than it’s advertised horsepower.
but who drives for 24 hours solid? I mean, I have an LS2 GTO and I love it, but would prefer LS3 for sure. and I have never heard of a reliability issue with LS3. LS7, yes, but not LS3.
Ls2 over ls3 all day dyno speaks for itself.
Dyno speaks for itself? Explain please. I’m looking at getting one for a swap project…wondering if I should go that rout or LS3.
Keep in mind that the LS1 or LM7 is not necessarily a better deal than the LS2 or LS3. Indeed, these newer motors have their advantages that make them worth the extra cash. First of all, a common arguement against the LS2 or LS3 vs the LS1 or LM7 is that, with the extra cash you have, you can modify the cheaper motors to be better. This may be true. But there are caveats. One if having a nice, wide power curve with lots of torque. Simply put, the greater displacement of these newer LS motors puts them ahead of the older motors. When modified to try to make up for the difference, the older motors will ALWAYS be peakier, burn more gas, possibly have problems passing emissions testing, and likely be less reliable. There is just something to be said for having the power you want from an engine that is BONE STOCK. And the LS2 and LS3 give you this over the LS1 and LM7, and in a package that is no bigger physically (also, no heavier than the LS1 and LIGHTER than the LM7).
Another factor to consider is heads. The LS3 heads are LOTS better than the LS1/LM7 heads, and somewhat better than the LS2 heads. But with its 4 inch bores, the LS2 can also benefit from LS3 heads. Neither the LS1 nor the LM7 can.
Smog is another consideration. Emissions equipment actually for SIMPLER on the newer engines. Neither the LS2 nor the LS3 has either EGR or air injection. Some years of the LS1 and LM7 have EGR. And almost ALL have air injection. This makes engine swaps both more complicated and less clean looking under the hood, at least if you are trying to be emissions compliant. It also introduces more failure points. Simply put, less smog gear is better.
Finally, the LS2 and LS3 have the advantage of coming from higher end vehicles vs most LS1 and LS7 applications. This means that motors were likely better taken care of. Combined with the fact that these motors are newer, you are MUCH less likely to end up with a motor that has issues.
Well done and well said. Go LS2.
It is good to hear the ls2 is better than ls3 for the sake of just 200hp..!
Has anybody got any ideas for the ls2 amission test as my last mot it was so close to failing next year it may fail
I have a 05 Vette and one lifter roller had its bearings start to go and caused a small flat spot on the roller and slight damage to the lobe on the cam. I face the decision now to replace the cam or not and if I do what cam to use. I am an old fart and do not need to increase the power of the car but a better sound and as good or better mileage would be nice. Cost is also a factor so wondering if a stock LS3 cam will work in the LS2 without other changes like different lifters, push rods or rockers although I would be changing the lifters anyway and push rods are not expensive.
I’m wondering the same will a ls3 cam work in a ls2 without changing anything else.
If the Gen IV LS2 is better than than the Gen IV LS3, isn’t it foolish that Chevy would invest $millions to create an engine that is worse than its predecessor? The LS2 was only available for three model years 2005-2007 in the US while the LS3 was around for 10 model years 2008-2017 last used in the Chevy SS. I looked at the Chevy performance parts page https://www.chevrolet.com/performance-parts/crate-engines and there were no LS2 crate engines for sale.