[Editor’s Note: Find a comprehensive list of every LS and Vortec engine spec guide and upgrade guide we’ve published here.]
Chevrolet introduced the automotive world to the LS engine with the launch of the LS1 in the 1997 Corvette C5.
It left a mark.
The lightweight engine made big-block horsepower in a package no bigger than the engine-swapping community’s previous hero—the small block Chevy. Not only did the LS engine platform provide opportunity for making unprecedented power in a small-block mill, it did so while meeting modern fuel economy and emission standards.
In an automotive context, it’s not hyperbole to say the LS engine changed the world.
Because LS blocks share similar exterior dimensions, the vast majority of LS engines can fit anywhere that a small block Chevy 350 can. They’re ideal for both tame daily driver builds, as well as high-performance street or race applications north of 1,000 horsepower.
We know you get it—LS engines are really popular. Even better—they’re pretty easy to find. Both factory and aftermarket LS parts are readily available. And dropping an LS motor into another vehicle—particularly any car or truck previously powered by a small block Chevy—is as simple as engine swapping gets.
As is often the case, the devil tends to be in the details. So we’re going to deliver those details, and we’re not going to take anything for granted in the process.
There are several engines within the LS family. So if you’re going to swap or modify an LS, the first thing you’ll need to know is which particular engine you have or want, and how to find it (should you choose to not go with one of the many LS crate engines available). That means understanding the various technical nuances of each LS RPO code, so you know which new parts to buy, or what old parts to salvage on your next trip to the junkyard.
Know Your LS Engines
Even among experienced mechanics and auto enthusiasts, there is a lot of confusion about General Motors’ naming convention for the LS engine series. We’re going to clear up as much uncertainty as we can.
1. It Doesn’t Have to Say “LS” to be an LS Engine (Hello, Vortec)
It was automotive enthusiasts who gave the “LS Engine Series” its name.
Officially, there’s no such thing. What we call the LS engine series is really just all of the engines from General Motors’ Gen III and Gen IV small-block V8 groups.
If you want, you can imagine the LS engine series kind of like a group of celebrities—people like Oprah Winfrey and Ben Affleck—who were given honorary doctorates from Ivy League universities, and then afterward everyone actually started calling them Dr. Winfrey and Dr. Affleck.
“Congratulations, Dr. Affleck. I thought you were amazing in Gigli, and your interpretation of Batman is definitely just as good as Christian Bale’s,” the president of Brown University probably said.
Much like that very realistic scenario, Chevy’s L76 and L77 engines are actually LS engines.
And though the majority of people might call them Vortec engines, GM’s small-block 4.8L, 5.3L, 6.0L, and 6.2L truck engines from 1997 through Gen IV are still very much members of the LS engine family.
The LS1 was the first mill from GM’s Gen III small-block engine platform. Then, the 385-hp LS6 made its appearance in the 2001 Corvette Z06, and everyone just sort of latched onto the “LS series” name.
But if we’re going by the book (and we’re not—we just want you to get it), the LS1 and LS6 are just two of several Regular Production Option (RPO) codes in GM’s Gen III engine book.
In fact, there have already been LS engines—the original Chevy 454, for example. It was introduced in 1970 and came in three variants: the LS5 (an RPO code you won’t find in the modern LS family), the LS6, and the LS7. So, if you’re one of the people who think it’s all a little confusing, you’re not weird. It’s actually confusing and you probably don’t need a lobotomy.
There are at least 25 RPO codes within the LS engine platform that don’t contain the letters “LS” at all (though they do all begin with the letter L). You’ll find the full list below in our LS Engine Family Tree.
2. The LS Engines Were Not Released in Sequential Numerical Order
This should be obvious if you paid attention to that last note. But it might bear repeating. Even though it would make sense to the majority of people, GM didn’t release the LS2 immediately after the LS1. That would have made it too easy. The LS6 came next.
But GM also launched two LS truck engines before unleashing the LS6—the 4.8L Vortec (LR4) and the 5.3L Vortec (LM7, L59, LM4, L33). Sometimes, the only differentiator between these engines is the block material: cast iron or aluminum—another subject we’ll dive into further as we explore the LS engine universe.
3. ‘Wait a Minute… We Can Use Easy-to-Find Truck LS Engines for Swaps?’
Yep. Fun, right?
But there are all sorts of Ifs, Ands, and Buts to think about, depending on your specific application. We’ll tell you as much as we can. Near the bottom of this article, you’ll find a still-growing list of LS and LS-based truck engine specification guides and comprehensive engine upgrade guides. These guides are full of all kinds of expert LS-engine wisdom, courtesy of our friends at Summit Racing.
4. One of These Things is Not Like the Others (Spoiler: It’s the LS4)
The LS4 is the oddball of the LS series. There’s a VERY good chance that it’s not your friend and will openly mock that Def Leppard poster you have hanging in your garage.
The LS4 is designed specifically for transverse front-wheel drive applications, unlike every other LS-based RPO code. Unless you like to fabricate (a lot!), you’ll probably save yourself trouble by steering clear of the LS4.
5. Don’t Confuse Gen III—the First Half of LS Engine History—with “LS1”
You’ll sound silly AND get the wrong parts—two things best avoided. We have it on good authority that several people refer to ANY LS engine from the third generation of Chevy small blocks as an “LS1.” It would be helpful to everyone in the world if that stopped happening.
There are several ways to identify an LS engine, and we intend to teach you all of them.
One way is simply to know which LS engines came in which GM vehicle models (if you can be sure a particular vehicle is housing its original engine).
The lifetime of the LS engine series can be split in two halves—Gen III and Gen IV. Gen III spanned from 1996 to 2007. And Gen IV spans from 2005 through today. With the all-new Gen V 6.2L LT1 (released for the C7 2014 Corvette Stingray), new LS engine production could be nearing its end, but we assure you that people using LS powerplants to make their vehicles go won’t stop for a very long time.
To wrap your head around the group of engines that make up the LS engine family, we think it’s helpful to understand the architecture of the LS family tree, so we’re going show you how that looks.
The LS Engine Family Tree
Forgive us for not making it actually look very family tree-like. But this is a high-level look at the LS engine family that you might find useful.
LS Vortec Truck Engines - Generation III (1999-2007)
LS Car Engines - Generation IV (2005-Present)
|5.3L||LS4||*Only LS engine with unique transverse FWD motor mount design|
|6.0L||LS2||*GM put the LS2 engine in both cars and trucks|
|L76||*GM put the L76 engine in both cars and trucks|
LS Vortec Truck Engines - Generation IV (2007-Present)
|6.0L Vortec||LS2||*GM put the LS2 engine in both cars and trucks|
|L76||*GM put the L76 engine in both cars and trucks|
Bonus LS Engine Notes:
- LS engine blocks are either cast iron or aluminum. All car engines had aluminum blocks. Truck engines could be either material.
- With the noted exception of the early LQ4 engine, all LS engines have aluminum cylinder heads.
- The LS2 and L76 are noteworthy in that they are both Gen IV 6.0L aluminum block engines, and that they came from the factory in both cars and trucks. Each came with different accessory drives, intake manifolds, and oil pans. They also had different VIN codes.
- The LS364 is a carbureted Gen IV crate engine GM makes exclusively for the aftermarket.
- LSX came to market as a bare engine block for retrofitting and swapping, and is now available as both an LSX 454-cubic-inch (7.4L) crate engine, and LSX 376-cubic-inch (6.2L) crate engine.
LS Engine Spec Information & Engine-Specific Upgrade Guides
We created a series of comprehensive LS engine spec guides and engine upgrade guides by RPO code. You can find them all here:
Gen. III LS Engine Upgrade Guides & Specs (1996-2007)
|Gen III LS & Vortech Engines|
|Displacement||Engine Code||LS Engine Upgrade Guide||LS Engine Spec Guide||Reluctor||VIN (8th Digit)||Block||Head||Gen III Years||Vehicle|
|4.8L||LR4||LR4 Upgrade Guide||LR4 Engine Specs||24X||V||Iron||Cathedral||1999-06||Truck/SUV/Van|
|5.3L||LM4||LM4 Upgrade Guide||LM4 Engine Specs||24X||P||Alum.||Cathedral||2003-05||SUV|
|5.3L||LM7||LM7 Upgrade Guide||LM7 Engine Specs||24X||T||Iron||Cathedral||1999-07||Truck/SUV|
|5.3L||L59||L59 Upgrade Guide||L59 Engine Specs||24X||Z||Iron||Cathedral||2002-07||Truck/SUV|
|5.3L||L33||L33 Upgrade Guide||L33 Engine Specs||24X||B||Alum.||Cathedral||2005-07||Truck|
|5.7L||LS1||LS1 Upgrade Guide||LS1 Engine Specs||24X||G||Alum.||Cathedral||1997-04||F body/C5/GTO|
|5.7L||LS6||LS6 Upgrade Guide||LS6 Engine Specs||24X||S||Alum.||Cathedral||2001-05||C5 Z06/CTS-V|
|6.0L||LQ4||LQ4 Upgrade Guide||LQ4 Engine Specs||24X||U||Iron||Cathedral||1999-07||Truck|
|6.0L||LQ9||LQ9 Upgrade Guide||LQ9 Engine Specs||24X||N||Iron||Cathedral||2002-07||Truck|
Gen. IV LS Engine Upgrade Guides & Specs (2005-Present)
|Gen IV LS & Vortech Engines|
|Displacement||Engine Code||LS Engine Upgrade Guide||LS Engine Spec Guide||Reluctor||VIN (8th Digit)||Block||Head||Gen IV Years||Vehicle|
|4.8L||L20||L20 Upgrade Guide||L20 Engine Specs||58X||A||Iron||Cathedral||2010-17||Truck/Van|
|4.8L||LY2||LY2 Upgrade Guide||LY2 Engine Specs||58X||C||Iron||Cathedral||2007-09||Truck|
|5.3L||LY5||LY5 Upgrade Guide||LY5 Engine Specs||58X||J||Iron||Cathedral||2007-09||Truck/SUV|
|5.3L||LC9||LC9 Upgrade Guide||LC9 Engine Specs||58X||3 or 7||Alum.||Cathedral||2007-14||Truck/SUV|
|5.3L||LH6||LH6 Upgrade Guide||LH6 Engine Specs||24X/58X||M||Alum.||Cathedral||2005-09||SUV|
|5.3L||LH8||LH8 Upgrade Guide||LH8 Engine Specs||58X||L||Alum.||Cathedral||2008-09||Truck/SUV|
|5.3L||LH9||LH9 Upgrade Guide||LH9 Engine Specs||58X||P||Alum.||Cathedral||2010-12||Truck|
|5.3L||LMF||LMF Upgrade Guide||LMF Engine Specs||58X||4||Iron||Cathedral||2010-14||Vans|
|5.3L||LMG||LMG Upgrade Guide||LMG Engine Specs||58X||0||Iron||Cathedral||2007-14||Truck/SUV|
|5.3L||LS4||LS4 Upgrade Guide||LS4 Engine Specs||24X/58X||C||Alum.||Cathedral||2005-09||FWD car|
|6.0L||LS2 (Car)||LS2 (Car) Upgrade Guide||LS2 (Car) Engine Specs||24X/58X||U||Alum.||Cathedral||2005-2007||Corvette/GTO/CTS-V|
|6.0L||LS2 (Truck)||LS2 (Truck) Upgrade Guide||LS2 (Truck) Engine Specs||24X/58X||H||Alum.||Cathedral||2005-06, 2007-09||SSR/TBSS, TBSS/9-7X Aero|
|6.0L||L76 (Car)||L76 (Car) Upgrade Guide||L76 (Car) Engine Specs||58X||Y||Alum.||Rectangle||2008-10||Pontiac G8|
|6.0L||L76 (Truck)||L76 (Truck) Upgrade Guide||L76 (Truck) Engine Specs||58X||Y||Alum.||Rectangle||2007-09||Truck/SUV|
|6.0L||L77||L77 Upgrade Guide||L77 Engine Specs||58X||2||Alum.||Rectangle||2011-17||Caprice PPV, Holden VE2/VF|
|6.0L||L96||L96 Upgrade Guide||L96 Engine Specs||58X||G||Iron||Rectangle||2010-17||Truck/SUV/Van|
|6.0L||L98||L98 Upgrade Guide||L98 Engine Specs||58X||N/A||Alum.||Rectangle||2007-08||Holden|
|6.0L||LC8||LC8 Upgrade Guide||LC8 Engine Specs||58X||B||Iron||Rectangle||2011-16||CNG fuel|
|6.0L||LFA||LFA Upgrade Guide||LFA Engine Specs||58X||5||Alum.||Cathedral||2008-09||Hybrid Truck/SUV|
|6.0L||LY6||LY6 Upgrade Guide||LY6 Engine Specs||58X||K/N||Iron||Rectangle||2007-14||Truck/SUV/Van|
|6.0L||LZ1||LZ1 Upgrade Guide||LZ1 Engine Specs||58X||J||Alum.||Cathedral||2010-13||Hybrid/Truck/SUV|
|6.2L||L92||L92 Upgrade Guide||L92 Engine Specs||58X||8||Alum.||Rectangle||2007-08||SUV|
|6.2L||L94||L94 Upgrade Guide||L94 Engine Specs||58X||F||Alum.||Rectangle||2010-14||SUV|
|6.2L||L99||L99 Upgrade Guide||L99 Engine Specs||58X||J||Alum.||Rectangle||2010-15||Camaro (auto)|
|6.2L||L9H||L9H Upgrade Guide||L9H Engine Specs||58X||2||Alum.||Rectangle||2009-14||Truck/SUV|
|6.2L||LS3||LS3 Upgrade Guide||LS3 Engine Specs||58X||W||Alum.||Rectangle||2008-17||Performance Cars, C6 Grand Sport|
|6.2L||LSA||LSA Upgrade Guide||LSA Engine Specs||58X||P||Alum.||Rectangle||2008-15||CTS-V, 5th Gen ZL-1|
|6.2L||LS9||LS9 Upgrade Guide||LS9 Engine Specs||58X||T||Alum.||Rectangle||2009-13||Corvette ZR-1|
|7.0L||LS7||LS7 Upgrade Guide||LS7 Engine Specs||58X||E||Alum.||Square||2006-15||C6 Z06, Camaro Z28|
(OnAllCylinders contributors Paul Spurlock and Brian Nutter from Summit Racing contributed to this article.)