LS Swaps Are Harder Than You Think, Here’s Why

If you search the Internet, you will find that LS swaps are “super easy and can be done with little to no money at all.” It seems that this engine just magically jumps in the car with zero headaches. The truth is, depending on your vehicle of choice, converting your project over will take some time and cost you more money than you think. Is there someone out there who could swap the engine over the weekend for $19.99? Maybe…but in our experience, that’s not the case.

Choosing The Right Car For A Swap

While some vehicles already have a good aftermarket following when it comes to LS-swap parts, others do not. Take a Squarebody Chevrolet Truck, for example. Companies like Holley offer virtually everything you need to perform a trouble-free conversion. You can purchase engine mounts, transmission mounts, fuel system, exhaust, oil pan, and even a radiator from its website, making for a simple swap. The problem is, convenience costs money, and the price of all of these parts can quickly add up. 

On the flip side, if you want to swap a vehicle that isn’t as popular, you will invest a lot of time doing research and fabricating components. The odds of finding something close that will work is pretty good with all of the offerings on the market. But, this is a trial and error process that takes time. 

The Fuel System

Most swaps will take place in a vehicle that is either carbureted or fuel injected. If you’re swapping a carburetor for EFI, you will need to add an electric fuel pump, fuel pressure regulator, EFI fuel filter, and a return line to the fuel tank.

If your car or truck already had fuel injection, then you will need to check to ensure your fuel pump can supply the LS with enough fuel. If it can’t, then a new fuel pump is in order. Either way, expect to need a new fuel pump, pressure regulator, custom hoses, and be ready to modify existing components. Holley, Deatschwerks, and Aeromotive all offer solutions for any fueling needs you might have.  

Electrical

There are a ton of do-it-yourself LS harness videos on YouTube. While many people take the factory harnesses and convert them to stand-alone, it’s a time-consuming and monotonous process. If you plan on going this route, make sure to start with a good harness. You will want to find a new one that has not been cut or modified in the past. Do your research and take your time with this process… if you don’t, there will be repercussions down the line. Our advice is to purchase a new standalone. — you will be thankful in the long run, especially if you’re not experienced with the wiring process. BP Automotive, SpearTech, and Howell EFI are all excellent sources to check out. 

Building your harness takes a lot of time and is a dirty process. In our opinion, you would be way ahead of the curve by purchasing a new harness.

Another area that’s usually an afterthought is gauges. Older vehicles tend to be easier to deal with because the ECU does not run them. In most cases, you can add the factory sensors with adapters that are independent of the engines. Mechanical gauges like oil pressure and water temperature will still function normally inside the vehicle. If your car has electronic gauges that are ECU-driven, it gets a lot more complicated. In some cases, a CAN bus(Controller Area Network) will need to be used to convert the signal so the gauges can operate correctly. 

The LS alternator is another component that can be a little tricky to deal with in an older vehicle. Without going into too much detail, getting the alternator to fire and shut off can be a problem that can either leave you with a dead or overcharged battery. However, Holley has a solution with its alternator plug (PN 197-400). This product will save you a ton of time when wiring the electrical system. The weather-pack connector has a resistor inside, allowing the alternator to function correctly, and all you need to do is hook up one wire. 

Tuning

Now that you’re getting close to firing the project, what are you going to do about tuning? There are a few options here. You can either do it yourself, find a reputable tuner, or use a mail-order tuning service. No matter which route you go, it’s going to cost you money unless you already have a tuning program or a self-learning ECU like Holley’s Terminator, Edelbrock’s Pro-Flo 4 and FiTech EFI.

Exhaust

Odds are you can use the OEM cast iron manifolds for most swaps. Typically they tuck in pretty tight, allowing room to get the exhaust pipe down through the frame rails. From there, you will need to either fabricate an exhaust system or take the vehicle to a muffler shop. If you want to go with a set of headers over the manifolds, some companies offer complete exhaust systems that simply bolt-on. While this is by far the easiest method, it comes with a cost, of course. 

While the factory cast 5.3-liter cast manifold would have cleared the Suburban frame, we opted for a set of Doug Thorley Headers instead.

Accessories

While the truck accessory drive will work in a few different vehicles, sometimes the A/C compressor hits the frame, causing issues. If you’re not planning on running air conditioning, GM made it simple to remove the compressor and bracketry. The compressor also has its own belt and is not a part of the serpentine system, which can be removed without affecting the other accessories. 

Holley’s R34 bracket bolts on the LS and works with the rest of the factory 5.3-liter truck accessory drive making the installation a snap.

If you are planning on running A/C, and the OEM compressor doesn’t clear, then you will either need different brackets or a new accessory drive system. Companies like Holley, Concept One, ICT Billet, Eddie Motorsports, Billet Specialties, and Dirty Dingo have various options depending on your needs and budget.  

Making Room

Sometimes the LS engine just doesn’t fit. It’s not uncommon for the LS oil pan to hit a crossmember. To fix this dilemma, you could either run adjustable motor mounts to move the engine forward or backward. In some cases, you might be able to get by merely by modifying a crossmember or frame for added room, but sometimes you will not. If you can’t, Holley, Moroso, and Chevrolet Performance all offer aftermarket LS swap oil pans. These products are more compact, giving you added clearance where it’s needed.

We got lucky on our Suburban swap. This small modification to the cross member was all that was needed to clear the truck oil pan for our project.

In The End

LS swaps can be relatively easy, depending on the popularity of vehicle used and available budget. However, if you choose a car or truck off the beaten path, you may find yourself spending more time doing research and fabricating parts and pieces to make it work. While it is possible to swap an engine over a weekend, believe us when we say you have a lot of homework to do. 

About the author

Brian Havins

A gearhead for life, Brian is obsessed with all things fast. Banging gears, turning wrenches, and praying while spraying are just a few of his favorite things.
Read My Articles

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