LS1 vs LS3: Which One is Actually Better?

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 is extremely similar. The Gen IVs 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 LS1 and the LS3 have a lot in common. But, the most obvious difference between the two is the displacement.

The LS1 has 5.7L of displacement and technically was the first Gen III Chevrolet engine. The LS3, on the other hand, has 6.2L of displacement and is a 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. With the given age gap between these two engines, what was Chevrolet able to improve upon? So, let’s dive in, and compare LS1 vs LS3.

LS1 vs LS3: Cylinder Heads

One of the most important parts of any performance engine is the cylinder head(s). Things like port shape, size, and length have a massive effect on the performance output.

Luckily when Chevrolet built the LS family they knew how to make really good cylinder heads. As a matter of fact, LS7 heads flow nearly as well as Nascar heads! But what about the LS1 and LS3?

LS1 flow numbers: 244 cfm intake, 206 cfm exhaust. Pretty impressive for completely stock production heads.

LS3 flow numbers: 293 cfm intake, 244 cfm exhaust. As you can tell, Chevrolet continued to innovate and design better heads throughout the LS family’s lifetime.

All numbers quoted were at .700″ lift.


RELATED: LS1 vs LS2: Which One is Actually Better?

So it’s not really a huge surprise to LS enthusiasts that the LS3 heads are pretty amazing. They outflow LS1, LS2, and LS6 heads by 50 cfm on the intake side. That’s a massive amount.

But, unfortunately, you can’t really just bolt LS3 heads onto an LS1 due to the LS3 heads needing a minimum cylinder bore of 4″.

LS1 vs LS3: Intake

Just like everything else in this comparison, the later engine was better in nearly every single way. The LS1 and LS3 intake are somewhat similar but have quite a few differences.

First of all, the LS1 intake manifold is designed for the cathedral port heads (LS1, LS2, LS6, and truck heads). So, unfortunately, you can’t just bolt an LS3 intake onto an earlier LS.


RELATED: LS2 vs LS3: Which One is Actually Better?

Chevrolet also increased the LS3’s intake manifold flow by straightening out the intake runner and optimizing the flow path to the heads.

The LS3 intake is designed for the later rectangle heads. The LS3 intake produces about 10-20 horsepower more than the LS1 intake. But, if you want the LS3 intake you also need LS3 heads, and a 4.0″ bore block.

LS1 vs LS3: Cost

So by now, I’m sure you know that the LS1 was the first engine to be released in the LS family. It was also produced in fairly large numbers. It was C5 Corvette engine until the LS2 came around, it can also be found in the Camaro SS.

The LS3, on the other hand, didn’t come around until 2008. Much like the LS2 it replaced, it was the new base Corvette engine. The LS3 also came in 2010-2015 Camaro’s, and various other Chevrolet vehicles.


RELATED: Ford Modular vs Chevy LS: Which One is Better and Why?

Why am I telling you what cars the LS1 and LS3 came in? Because that’s a large factor when it comes to pricing.

The LS1 is more abundant than the LS3, which brings the price down quite a bit. The LS1 is also older, which also makes it cheaper.

So, to no one’s surprise, the LS1 is cheaper. An entire LS1 drivetrain can be picked up for about $1000+ less than an entire LS3 drivetrain.

LS1 vs LS3: Which One Should I Swap?

The Chevy LS is pretty much the go-to swap when you’re looking to upgrade your engine. But which LS should you swap? The LS1 or the LS3?

This can be pretty dependent on your budget. If you’re willing to cut some corners elsewhere on your car to afford an LS3, I say do it. If you are on a tight budget then the LS1 will work perfectly for you.


RELATED: 6 Reasons Why the Chevy LS is so Good

The LS1 and LS3 are going to be almost identical as far as the swap process, so you might as well get the more powerful engine if possible.

Both are very easy to swap thanks to the simple wiring harness of the LS. The wiring harness allows the LS to run on its loop, so it has no idea what’s going on with the rest of the car.

So Which One is Better?

Much like the LS1 vs LS2 debate, the later engine is the better one. The LS3 makes more power than an LS1 and has more potential at the end of the day.

The LS3 has better heads, a better intake, and a bigger displacement. But, price limits nearly every car guy. We must pick and choose our parts in order to stay within our allotted budget. For that reason, many of us will end up picking the LS1.

Although we would all love to have to bigger, and better LS3. Most of us just can’t afford it. Like I said in the LS2 vs LS3 debate, I would personally rather have an aluminum 5.3L from a Tahoe.

It’s a much cheaper option and it’s nearly just as good as the LS1. All the money you save going with a 5.3L can be put into a set of top-of-the-line cylinder heads.

16 thoughts on “LS1 vs LS3: Which One is Actually Better?”

  1. What you didn’t mention is the ls3 heads bolts right up to the ls2 block and ls1 blocks if you run a smaller intake valve.

    • They are not an identical swap There are more than a few changes for swapping. The most important being the timing sensor gear on the crank. It has to match your computer. The next is the cam sensor and or cam gear.

    • Sir I would like to know about the LS3 engine. I have a 2009 Chevrolet Impala 3.9 LTZ, want to will that engine fit into my car without any problems? Thank you please let me know.

    • If you have to put smaller valves in the LS3 heads to match the LS1 or LS2 block you would be defeating the purpose. You would be better off saving the money $$$ by just sticking with the LS1 heads and block. LOL

    • I have a 2004 c5 base model corvette, I would like to put a up grade cam kit # TSP 231-246 Stage 3 in it. What stall would you recommend. This car is for show, very little highway like to run A/C at times.

  2. My choice was a 6.0 liter iron truck engine. It has a 4″ stroker crank, giving it 408 cu in and uses the L92 heads. They are identical to the LS3 heads except for the valves. The LS3 has hollow stem intakes and sodium filled exhausts and can be directly swapped to the L92’s. I debured and smoothed the ports and blended the valve seats and port matched the intake manifold running a carb vs FI helping the budget. Theres many cam choices snd I chose a mid range Comp with GM Performance rollers. It runs awesome.

  3. What is the best engine for a 197p Blazer? I want power on the road and off. Should I do an LS or something? Which LS if it’s to be an LS?

  4. In 2016 we replaced original 1929 straight 8 engine/transmission of 1929 Pierce-Arrow 7-pass sedan 133 wheel-base, Model 125 with a used LS-1 engine/transmission from a Pontiac Firebird. It had more than 200,000 miles on it. I put another 14,000+ miles on it (unable to drive much in 2018 due to husband illness and of course no Club tours or local events in 2020). I did finish last year with a 1,500 mile tour in October. Engine knock bugged my husband and he is planning on getting a new crate LS-3. Question: does the LS-3 have the same footprint as the LS-1. The engine compartment of the 1929 Pierce-Arrow has plenty of room height and lengthwise but is limited in width of the engine compartment. Will we have installation problems?


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