What is an LS swap?

What is an “LS swap.” For the past few decades, the idea of the LS swap, or putting a GM LS engine inside a car or truck that did not have one stock, has been gaining huge amounts of popularity. Not only are LS engines incredibly reliable and durable, but they are also very plentiful and have massive aftermarket support. Are you thinking about an LS swap for one of your vehicles in the future? In this article, I’ll go over the necessary basic info you’ll need to get started on your LS swap.

What is an LS Swap?

First, I’ll start with the basics: What is an LS swap? An LS swap is when you replace a car or truck’s factory installed engine with an LS engine. There are many reasons to do this, mostly related to increasing reliability, longevity, compactness, lightweight, and ultimately, performance. It’s often said that you can put an LS-engine into anything. While that might not be entirely true, the list of vehicle builds with LS engines is pretty incredible. 

The most common reason you’ll see an LS swap is to replace a blown or damaged engine. However, you’ll often hear of an LS swap referring to hot rods that are built from the ground up that utilize an LS engine. Hot rods have long favored using GM’s series of LS-engines, and they are very popular in them everywhere. 

What is an LS engine?

You might be wondering to yourself, what exactly is an LS engine? And why did swapping them recently become so popular? LS engines have proven themselves to be extremely reliable, able to run for lots of miles. Additionally, they are capable of some pretty hefty performance. In addition, LS engines are relatively compact and lightweight, so they can easily fit in a lot of engine bays. 

An LS engine essentially means any third of fourth generation General Motors/Chevrolet small-block V8 engine. The term LS comes from the very first engine from the series, the 5.7 liter LS1 engine inside the 1997 C5 Corvette.

Since then, GM has released more than 35 different variations of the LS engine, including the Vortec series. GM’s Vortec and LS series are the same except they call truck engines Vortecs and car engines LS. The only real differences are oil pans, intake manifolds, and engine tuning. Also, generally speaking, car engines used aluminum blocks while trucks could be aluminum or cast iron. All LS/Vortec cylinder heads are aluminum except the 6.0 LQ4.

GM made the LS/Vortec series in displacements ranging from 4.8 liters (293 cid) to 7.0 liters (427 cid). While GM made the vast majority of LS naturally aspirated from the factory, both the LSA and LS9 received superchargers. Chevy no longer puts the LS or Vortec series inside their production cars. Luckily, they still have a number of LS blocks available for the aftermarket as crates.

Why the LS or Vortec engines?

Still, with all the available options out there, why the GM LS/Vortec V8s? There are quite a few reasons the LS/Vortec series have risen to the top of the list for swaps. For one, many consider the LS and Vortec lines to be the best V8 engines to have been built from the late-1990s to the mid-2010s.

They are relatively compact and lightweight, so they are easy to fit in tighter engine bays where other V8s might not. They are also known for being able to take some serious abuse and withstand lots of mileage without needing a full rebuild. A well maintained and built LS/Vortec can easily last more than 200,000-300,000 miles without breaking down. 

Additionally, they are relatively cheap to buy used and come in a huge variety of displacements. Of course, a brand new crate LS from Chevy performance won’t be cheap. Still, you can typically find smaller 4.8 and 5.3 liter Vortecs for less than $1,000 used or in a junkyard. Even the more powerful and sought out LS1 and LS3 engines can still be had for around $2,000 used. Making them very affordable for builds. 

Finally, the ultimate reason to choose an LS or Vortec engine for a swap is the performance potential. All LS engines make at least 250-300 horsepower stock, and that’s before we get into mods. With cam swaps, intake upgrades, and of course, superchargers and turbochargers, you can push many LS engines past 500 horsepower with ease. Many LS builds even crack the 1,000 horsepower mark with regularity when starting with the larger displacement versions. 

What do you need for an LS swap?

So what exactly do you need to complete an LS swap for your vehicle? Every swap is different. It depends on the donor car you’re using, the specific LS or Vortec engine, where the engine was sourced from, and more. While we can’t quite create a guide for every LS project, here are some of the basic parts you will need to get your swap underway. 

Basic LS swap parts: Engine, Transmission, and Mounts

First up, you’ll obviously need to pick out an LS or Vortec engine for your LS swap. They come in displacement from 4.8-7.0 liters, and all except the LS9 and LSA are naturally aspirated. Many will choose a smaller 5.3 Vortec due to their cheapness and ability to surpass 400-500 horsepower relatively easily. 

However, if you are searching to make some big power or are looking at hauling, towing, etc., you might want to start with a larger power plant like the 6.0 liter LS2 or the 6.2 liter LS3. Compression will also be a factor, depending on if you plan on adding boost. Boosted engines will want something lower and closer to 9.5:1. 

For the transmission, you have a ton of different options. Most common are the slightly older Borg Warner/Tremec T-56 and the newer Tremec TR6060. Both are six-speed manuals, bolt right up to LS engines, and are extremely strong. Older automatic options are the TH350, TH400, TH700R, and 460LE — though the first three require a flexplate adapter to bolt up successfully. 

Finally, after you have your transmission and engine combination picked out, you’ll need to look at motor mounts and potentially adaptor plates. Since your vehicle did not originally come with an LS engine, it was not designed to house it or your transmission. At a minimum, for the transmission you will need a crossmember mount to support it. For the engine, you will need either new engine mounts or adaptor plates to fit to the existing mounts in the vehicle already. 

Now that you have your engine, transmission, and supporting mounts figured out, let’s move to the next step, wiring and electronics. 

Wiring, ECU/TCU, and Gauges

Besides the engine and transmission combination, figuring out a wiring and engine control unit (ECU) solution will be the most important parts of your LS swap. Without a wiring harness, your engine will not be able to connect the fuel injection system to the ECU. Thus, the engine will not run. There are many companies that make wiring harnesses for the various LS/Vortec engines. Additionally, if you are buying a crate engine package from Chevrolet most of this will be included with the purchase. 

For the ECU, in some cases you can reuse the ECU that came with the car if you can get it. But often, they are damaged and not available to the buyer. However, most people opt to run their own standalone ECU for the best tuning and performance potential anyways. These are not cheap, but some of the best options are the AEM EMS and Holley Dominator. Additionally, if you have a newer automatic transmission, some of them require a transmission control unit (TCU) to run properly. 

After you get your wiring and ECU picked out, you will want to make sure you route some gauges. At a minimum, you’ll want air-to-fuel ratio, boost pressure (if using forced induction), and oil pressure. These are to make sure your engine is running healthy at a glance and not losing oil pressure or running lean. 

Basic LS swap parts: Intake, Exhaust, and Oil Pan

Next up on your LS swap list is figuring on the intake manifold, exhaust manifold/headers, and the oil pan. A lot of this will depend on the limitations of your engine bay for what you can fit. Some builds will require a low-riser intake manifold that sits lower, while others will have more space for a traditional or high-riser style manifold. 

Many LS and Vortec oil pans are interchangeable. So, it will be a matter of finding one that fits with your particular engine without (hopefully) too much shaving and manipulation. The oil pan is extremely crucial, so you need something durable that still fits. For the headers, the biggest issue will be finding ones that fit and clear everything under the donor car. For older more common swaps, there are many header options out there. More obscure swaps will require custom made headers. 

Other Parts

Finally, you’ll need various other parts to make sure your engine starts and runs. These include a starter, accessory system (A/C, alternator, power steering pump, tensioner, etc.) and serpentine belt, revised driveshaft, new differential, new brakes, a throttle body (will depend on ECU for drive-by-wire or cable-throttle), new sensors, radiator, and a new air intake. It’s certainly not a small list, but remember you are starting from scratch and need everything for a modern engine to run. 

What is an LS Swap Summary

As you can see, an LS swap is certainly not for the faint of heart. On average, they can cost anywhere from $1-2 thousand to $10-20 thousand depending on where you are sourcing your engine from, how much power you intend on making, and everything else you decide to customize. There is no standard LS swap, and all of them have their own unique problems and rewards. However, few people complain about a fully working LS swapped vehicle, and they tend to rate very high on the smiles per gallon chart. Is an LS swap right for you? Let us know what you’re thinking in the comments below!

What is an LS Swap FAQ