8 Ways to Make Your LS Swap Easier – and the vehicle that’s easiest to LS Swap

Despite what you see on Instagram, swapping an LS engine into your project vehicle isn’t always simple or easy.

There are a few ways you can make the process go smoother though, and a lot of these have to do with what vehicle you choose to do your LS swap in. If you’ve already chosen a vehicle, you’re kind of stuck with what you’ve got, but hopefully some of these concepts will still be helpful.

So here are my 8 ways you can make your LS swap project easier, which will also make it quicker and cheaper. What we want to avoid is becoming a “Jackstand Johnny” whose project vehicle sits on jackstands in the driveway until his wife gets tired of looking at it and he sells it as a pile of parts for a fraction of the money he has into it.

As a bonus at the end I’ll throw in my opinion of what vehicle is the easiest to LS swap.

1. Don’t re-invent the wheel.

Choose a vehicle for your LS swap that has been done before and has parts commercially available. I’d recommend choosing a GM truck or SUV (particularly square body or OBS body style,) a GM G-body, GM muscle car (Camaro/Firebird/Chevelle, etc,) a Fox body, SN95 or New Edge Mustang. Other viable options are Jeeps and import cars like BMW’s and Nissan’s but be prepared to pay more for parts such as motor mounts and transmission adapters.

2. If you’re on a tight budget, choose an engine/transmission combo that doesn’t require an adapter.

There are two ways of accomplishing this. One is to use a transmission that came behind an LS engine from the factory, typically a 4L60E or a 4L80E. A 6L80E would also work but would add to the cost and complexity of the project which is what we’re trying to avoid. Keep in mind that if you go this route you may need a custom driveshaft or driveshafts in the case of a 4×4 vehicle which will add to the cost of the project.

The other is to use an older GM transmission like the TH350 or TH400 that will bolt up to a newer LS engine. This is the route I’m going with my Suburban project. It already has a TH400 that will bolt right up to the 6.0L LS engine that I’ll be swapping in. At some point, I plan on upgrading to a 4L80E to get the overdrive which will help my fuel economy but initially I’m going to keep the turbo 400. This will allow me to use the existing driveshafts, keep my costs down, and get back on the road quicker.

3. If possible, keep the engine in the factory location.

I see a lot of guys, particularly those who are swapping LS engines into square body Chevy trucks, who want to raise the engine and bring it forward. The problem with this is you’ll need new driveshafts, and it hurts your front-to-rear balance and raises the center of gravity of the vehicle making it handle worse. I plan on using the square body LS swap mounts from DIY4X. These mounts can be seen here https://diy4x.com/product.php?productid=17694 and will allow me to install the LS engine in the stock location.

4. Choose a running donor engine.

If possible, make sure the LS engine that you are swapping in runs and works properly before swapping it in to your project vehicle. The best way of doing this is to pull your donor engine from a running and driving vehicle, that way you know that it is in good working order.

Since my engine was pulled from a vehicle in the junkyard, I’ll be building a test stand so that I can run the engine to ensure that it is working properly before I swap it into the Suburban.

5. If possible, get all of the related components from the same donor vehicle.

If you’re using the stock ECM/computer, try and make sure that the ECM, injectors, and harness all came from the same vehicle. If your donor vehicle has a drive-by-wire throttle, get the throttle pedal assembly and TAC module (if applicable) from the same vehicle as well. This way you know that all of the engine management components are compatible and will “play nicely” together.

6. Choose a vehicle to swap that came with fuel injection from the factory.

One of the hurdles you’ll run into with LS swapping an older carbureted vehicle is the fuel tank and fuel system weren’t designing for the high fuel pressures that the EFI system LS operates at. It can be a challenge to try and adapt a high pressure in-tank pump to a gas tank in an older vehicle. If choose a vehicle that came from that factory with fuel injection, it will already have an in-tank fuel pump and fuel lines that can handle the pressure that an EFI system requires. If the vehicle you are swapping the LS engine into is a TBI equipped vehicle you’ll still need to upgrade the in-tank pump, but it’s a fairly simple upgrade since the tank is already designed for an in-tank pump.

7. Choose a vehicle to swap that can use the truck intake, oil pan, accessory drive, etc.

One of the downfalls of LS swapping a car with a low hood profile like a BMW or 240SX is that it stock truck intake from a 4.8, 5.3 or 6.0L truck engine won’t fit under the hood. You also can’t use the truck oil pan and accessory drive. It’s not the end of the world but it’s another expense that will add to the total cost of the project and make it take longer. This can be avoided by choosing an LS swap project vehicle that has enough room to use the stock truck engine components.

8. Tackle the LS swap in stages.

You are not Gas Monkey Garage. Unless you have a team to work 20 hour days and help you reassemble the vehicle, don’t start your project by removing every nut and bolt and stripping your vehicle down to the frame. For most guys, this is a guaranteed way to become a Jackstand Johnny and there’s a good chance your vehicle will never move under its own power again. For me, I’m going to tackle my LS swap in phases.

The first phase will be getting the fuel system ready for the LS swap. I plan on installing a Walbro in-tank fuel pump that will put out enough pressure to supply the fuel system on an LS engine. I’ll use the stock supply and return fuel lines since my Suburban came with TBI. I’ll need a regulator that can regulate the pressure down so it’s useable with a carburetor. Then when it’s time to do the LS swap I can take out the regulator and just use the regulator on the stock fuel rails on the LS.

The next phase will be doing the actual LS swap. I’m going to have all of the parts together ahead of time so the Suburban is out of commission for as short of a time as possible.

The final phase will doing 4L80E swap but I want to get the LS running with the TH400 first.

Bonus: The easiest vehicle to LS swap

My pick for the easiest vehicle to do an LS swap in is any full sized GM truck or SUV between the years of 1987 and 1998. Whether it’s an 1987 C10, a 1987 to 1991 Jimmy/Blazer/Suburban, a 1988 to 1998 OBS truck, or a 1992 to 1998 Yukon/Tahoe/Suburban these vehicles are a great pick for someone doing their first LS swap for the following reasons:

  • They’ve been LS swapped lots so all of the information and parts needed to do an LS swap is readily available.
  • They come from the factory with TBI, so a simple fuel pump swap is all that’s need to get the fuel system LS ready.
  • The wiring (especially on the later Vortec-equipped vehicles) is very similar to the wiring on an LS-equipped vehicle so not much wiring modification is required.
  • An LS engine will bolt right up to the transmission that came with the vehicle
  • There’s plenty of room under the hoods the factory truck intake, oil pan and accessory drive will fit without much modification.

A close second would be an earlier square body GM but more fuel system modifications will be needed since the vehicle came with a carburetor from the factory. The other problem with the older trucks is wiring. The older the truck is, the worse shape the wiring is likely to be, and the more likely it is that the wiring is unsuitable for an LS swap. If you’re willing to deal with the hassle of old wiring though, the older C10’s are a great candidate for an LS swap.

3 thoughts on “8 Ways to Make Your LS Swap Easier – and the vehicle that’s easiest to LS Swap”

  1. A note on those engine swap plates. Have you looked at the $35 adapter plates that use the existing square body mounts and set the ls engine back one inch?

    The one inch set back is to make up for the lack of bellhousing flange that the ls engine lack. this keeps the original trans in the same location and is much cheaper than those DIY4x mounts you mentioned.

    Reply
  2. Im most of the way through my 79 c30 square body conversion to 4l80e. It wasnt far off the forum post on a suburban. My issue was low hump th350 trans cab. I used a 1 inch body lift. Only modification to make that work so far was drill holes on the fan shroud to lower it. I used factory mounts and sourced longer rear cab bolts. Truck looks great. Wiring it all will be interesting.

    Reply
  3. Im in the final stages of my swap. I’ve taken a 6.0 l from a 2001 2500. As far as electronics go.. Ive brought everything from the 2001 accept for the steering column and ignition. This is my 1st bump in the road. The morre internet education i get, the less I seem to know.
    Am i making a mountain of of a mole hill? What is the best way to get the key to fire this thing up? Help bro’s and sis’s….

    Reply

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