LS SWAP GUIDE BY ICT Billet LLC
We have years of experience with the LS engine swaps into various vehicles, which we have complied into our helpful guides to aid you in your LS swap. With every LS engine swap being different, this will guide you in what choices there are to be made, things you will need to keep in mind, as well as part numbers to get your swap completed. We offer options for various aspects of you swap such as motor mount conversion, transmission/ flexplate, wiring / computer systems, accessory drives, oil pans, headers / exhaust manifolds, engine oil and coolant adapters, fuel systems and carb conversions. We want to offer a guide which will make your LS swap as painless and trouble-free as possible.
MOTORS AND MOTOR MOUNTS
An “LS swap” is defined as taking a Gen 3 or 4, GM LS series, V8 engine and installing it into a vehicle that did not come from the factory with that style of engine. LS engines include all of the following RPO codes. (for more details click here for our RPO guide.)
Gen III: LS1, LM7, LR4, LQ4, LS6, L59, LQ9, LM4, L33
Gen IV: LS2, LH6, LS4, LS7, L92, L76, LY2, LY5, LY6, LC9, LFA, LH8, LMG, LS3, L98, LSA, L9H, LS9, L20, L94, LZ1, L99, L96, LC8, L77
The first step is planning your LS swap, by determining, which LS engine is going to work best with your build and budget. Starting with a junkyard truck engine is the most common and cheapest direction. The most abundant LS engines available are going to be the 4.8L, 5.3 L, and 6.0 L engines found in trucks and SUV’s. They are usually the most budget friendly and can be found in junk yards for as low as $400 for 4.8L, $700 for 5.3L, and 6.0L on Ebay for $1100 to your front door with 6 month warranty. These truck engines are almost always iron blocks, which will hold much more power than the aluminum blocks. If you plan to go with forced induction, whether it’s a turbocharger or supercharger, the iron block is the way to go, although the tradeoff is extra weight. You can find LS truck engines with aluminum blocks with the following RPO codes: LM4, L33, LH6, L92, L76, LC9, LFA, LH8, that will hold boost better than the LS1, LS2, LS3 engine blocks.
ALL-ALUMINUM LS1 ENGINES
The LS1 engine was the first engine on the LS platform. It was first released in 1997 in the Corvette and ran though 2004. In 1998 it was also offered in the Camaro and ran until 2002. These engines are sought after since they are all aluminum and lighter than other iron block LS engines, however they are getting harder to find and come with a higher price. The LS6 engine is another option with the same 5.7L displacement although is not commonly available used.
If you are wanting an all aluminum option but with larger displacement are more power than the LS1 there are the LS3 and LS7 engines. In 2008 GM released the LS3 in the Corvette then the Camaro followed in 2010. The LS3 engines ran until 2017 and on average a used engine costs around $2500 used. The LS7 engine is the largest displacement (7.0L) LS engine put in a factory GM vehicle.
Once you have decided which LS engine you will be using in your swap, next you will need to determine which mounts you will be using. Adapter plates are used in many builds which will bolt on to the factory location of the LS engine and adapt to the standard 3 bolt Small Block Chevy engine mount found in older GM vehicles. These style of adapter plates are adjustable and offer you the option of putting the LS in a factory position as well as 3 other setback positions for the adjustable plates. If you rather not reuse the 3 bolt clamshell mount, we do offer a steel conversion plate which will bolt directly to the LS engine and the frame mounts.
For more details and LS engine mounts click here
If you are not swapping a vehicle that came with a SBC, the popularity of LS swaps has grown so rapidly, there are many vehicle specific engine mounting kits available as well.
If you are wanting to keep your factory LS AC Compressor in its factory location, you may be able to do this, but it will depend on the clearance in your vehicle. Click here for a dimensional drawing of the factory compressor. In many applications the crossmember will interfere. One option is to notch the crossmember, which will require a welder and cut-off wheel. Not everyone is comfortable doing this, and in some cases, you still will not gain enough clearance. A second option is to move it higher on the passenger side of the engine. We do sell a kit for this and it is part number 551940-. From factory, the compressor is on its own 4 rib belt behind the other 6 rib accessory belt. With our kit it integrates the AC compressor into the same 6 rib accessory drive that the other accessories are on, which will require changing the clutch and pulley on the compressor as well. We do sell the 6 rib clutch needed, part number ACC506.
You will also need to choose which transmission you want behind your LS. You have many options depending on your budget as well as what your goal is with your swap as far as if you just want something to cruise or if you are building something more geared towards racing.
If you are sticking to a budget many people like the older GM TH350, TH400 or 700R4 transmissions. These non LS transmissions do require a crankshaft snout adapter for the crankshaft to converter as well as a flexplate with the correct holes for the torque converter. We offer both of these items, part number 551165 crankshaft snout adapter and 551356X flexplate with bolts.
The most common LS transmission to use will be the 4L60E. This will provide a smooth driving experience if you are just wanting something to cruise with and a good price point.
The 4L80E and 6L80E GM transmissions are somewhat more expensive than the 4L60E however they can handle more power and better reliability.
If you are doing a high horsepower application, you may consider sourcing a built transmission such as a Powerglide.
For those of you who want to bang through the gears for an exciting driving experience, we recommend the T56 or TR6060 transmissions. With the correct flywheel and clutch (sourced from the donor vehicle of your transmission), either of these transmissions can easily bolt up to any LS engine you are using.
Other popular options are the TKO500 and TKO600 transmissions. Many carbureted cars have already been converted to these modern 5-speed transmissions, however the input shaft isn’t long enough to reach the crank. To get around this, just swap the old bellhousing out for the GM 621 bellhousing. To do this you will also need a pilot bushing (GM Part Number: 12557583 or its equivalent) and an LS flywheel (Part Number: 12561680 or its equivalent). This particular flywheel is .400 inches thicker than the standard LS flywheel, which makes up for the difference of the LS crank being .400 inches further behind the bellhousing.
Adapter brackets are available from Street and Performance and Detroit Speed for mounting the hydraulic master cylinder to the firewall behind the brake booster. Or, with a drill press and some simple tools, you can always check out YouTube, get adventurous and make your own.
There are a lot of different ways to go about setting up your hydraulic clutch system, but some examples below will get you started in the right direction:
Hydraulic master cylinder adapter bracket
Or complete kit with master cylinder: Mcleod part number 1434002
If your donor engine came with an automatic transmission, then you will need to purchase a flexplate to adapt your torque converters bolt pattern click here. Also you will need a crank extension sleeve to support the center of the torque converter, click here. These 2 part are required if your transmission came from a non LS engine, regardless of vehicle year. Common transmissions to be re-used are the 4L60E, 4L80E, TH350, TH400, and powerglide.
There are countless options when it comes to the accessory drive system. It is a good idea to get the engine is in the vehicle and you have a better idea what clearance issues you may face. There are a few things to know and keep in mind when determining what brackets will work best with your application.
There are 3 different belt spacings on LS engines. If you are unsure which what your motor came out of you, can verify what spacing you have by looking at the crank pulley. We have the 3 options here in our tips and guides. You can also measure from the front face of the crank pulley to the front face of the block (not the timing cover but the block)
- Corvette / CTS-V / SS / G8 spacing is the closest to the block and measures 4.08” (engine block to outer edge of crank pulley). Most GM crate engines are sold with Corvette spacing unless special ordered.
- 1998 – 2002 LS1 Camaro / GTO spacing is slightly further out and measures 4.94”
- Truck / 2010-2015 LS3 Camaro spacing is the furthest out and measures 5.65” This spacing offers the most options with accessory placement. This is the only spacing which will allow you to put the alternator in front of the passenger side head. That can be ideal for turbo systems wanting to utilize up and forward headers or to have a cleaner look.
If you have the accessories that came from your LS engine you may be able to re-use them depending on where you are wanting to place them. Also if possible you will want to re-use your OEM power steering pump if possible to maintain the proper steering pressure (not light or heavy), which we at ICT Billet make many options to accomplish this install.
WIRING & COMPUTERS
The engine wiring harness can be an intimidating task in itself, although is rather straight forward. You can commonly take a Gen III wire harness that came with your LS engine, then grab your main firewall connector, remove the 2 orange wires which will now go to constant power. Next remove all pink wires, which are all going to be ignition switched. Connect a couple black ground wires, turn off your VATS (vehicle anti-theft system) in your ECM with HP tuners. See our basic wiring guide here. If you are not up to this task then you can buy a standalone type harness for around $550, which connects to a few power and ground wires and your done.
Typically “truck” oil pans will clear your front crossmember although in all cars, the oil pan will hang below the crossmember. Most commonly used is a holley 302-1 oil pan because it has the most clearance all the way around. It costs around $350. Most trucks can use a GM muscle car oil pan part number 551107.
Depending on your swap, the factory oil pan may have clearance issues. If this is the case, we have dimensional drawings here of many of the most popular oil pans which you can use to determine what may or may not work.
STEAM Crossover TUBES
GM designed the coolant steam crossovers in the top of the front and rear of the heads to allow pressure to equalize between the heads and help prevent hot spots. You will find in some truck engines GM blocked these off in the rear from factory. On some engines GM uses these crossovers and routes coolant to the throttle body to help warm the air upon a cold start of an engine. You have many options with your steam crossovers depending on your preference. If you choose to keep them, you can route them between heads or vent from the crossovers back to the radiator. Some people prefer to block them off completely, in which case it is important to ensure you have completely bled all air out of the cooling system with an air lift system. On the Gen V engines there are no longer steam port holes in the block.
You can find our many options of coolant crossover kits here
WATER PUMP SPACERS AND HOUSING
All of the LS Gen 3 and Gen 4 water pumps have the same bolt pattern and water jackets. Other than spacing the main difference is going to be where the water outlet exits the pump. Depending on your particular swap, you may find it is easier to use a different pump. For example a LS1 Camaro water pump has the outlet comes straight out the front, but if you are on truck spacing your water pump mounted on the block would be ¾” short of being inline with the crank pulley. The solution for this issue is water pump spacers which go between the block and the pump. They are offered in different spacings depending if you are trying to go from Corvette to truck or LS1 Camaro to truck spacing. Visit our tips and guides pages for all variations of these pumps.
Typically most people will want to retain their OEM dash gauges in their car. This is easily accomplished with our universal gauge kit below for coolant and oil.
Your engine ECM will not need your oil pressure, so you only need to keep your coolant temp. The heads on the LS engines are both the same, no left or right specific heads, so connect your ecm to one head and use our ICT gauge adapter to hook your vehicles coolant temp sensor to.
We suggest using a drop in EFI pump kit, such as Fitech 40015, which requires cutting a hole in the top of your fuel tank to add in a EFI unit. These are inexpensive and easy to install. You can then connect a C5 Corvette fuel filter/ fuel pressure regulator combo unit and plumb you’re an hoses to the engine.
Typically we use a header from speed engineering and a hot rod exhaust builder kit to complete the rest of the install. These 2 will typically cost you around $600.
If you want to retain a minimal wire harness, you can put a carburetor on your engine with a Holley 300-130 intake and coil module. This coil module will fire your coils based off of crank and camshaft sensor signals. Best of all these types of kits are plug and play and are extremely simple to install, and no timing to set.
LS swaps will power your ride with better performance, fuel economy, and most of all the reliability