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ICT Billet LS Swap Guide for Gen III & Gen IV

In order to get the most out of your LS swap, it’s important to understand the key factors that will be involved in your build. Learn how the different components come together and get all the details you need to become an LS swap pro. Download the full LS Swap Guide or select the individual guide to find the info you need from the list below.


Welcome to The LS Swap Guide presented by ICT Billet!

Below we will be touching on some of the key parts in your LS swap, and better understanding how the different components all come together. 

ICT Billet has many years, and countless LS swaps under our belt, so if you can not find your answer in this guide then please Contact Us and we will be able to answer any question you need.

We carry everything from LS swap mounts to adapters and wiring. 

Click the below links to take you straight to the section you would like to see, or feel free to scroll through everything.  

LS Crank Pulley (Harmonic Balancer) Swap Guide

One of the most important steps of your swap is to identify the "spacing" needed. This "spacing" is determined by the crank pulley that you have, or will be getting.

Here at ICT Billet we design our brackets based off these three spacing principles.

  • (-1) Corvette/CTS-V/SS(sedan)/G8's crank pulleys are in this category. See guide below for measurements
  • (-2) 1998-2002 Camaro/GTO's crank pulleys are in this category. See guide below for measurements.
  • (-3) All Truck/2010-2015 Camaro's crank pulleys are in this category. See guide below for measurements.

What this means to you?

All of our systems function around this spacing concept to ensure the kit is a direct bolt up to your application and proper functionality.

We categorize our parts by a 6 digit part # and a (-) at the end. Depending on which application the bracket was designed for would determine the last digit.

Example: Part# 551577-2 is a high mount alternator bracket for a LS1 Camaro. Same Part# 551577-3 is same bracket system but for a Truck engine with stock crank pulley.

Feel free to Contact Us if you have any questions!

Please visit store to shop ICT Billet Crank Pulleys

LS Water Pump Swap Guide

General spacing applies for the water pumps as well. You can NOT use any water pump on any LS based engine. Yes they will bolt up, but spacing is very important, same as pulley size, ect. However there is more adaptation for the water pumps with our water pump spacers.

Example: You can use a (-2) spacing LS1 water pump on a (-3) 5.3 truck engine.

What this means to you?

The ability to use different style water pumps will allow the build to be more universal. Most swaps are done to be as cost effective as possible.

Instead of buying a brand new water pump for your spacing just use ICT Billet Water Pump Spacers to make the one you have work! Make sure to keep in mind where the heater hose will run into the water pump when deciding on what water pump to use, what intake manifold, which ICT Billet Bracket to use, ect.

Feel free to Contact Us if you have any questions!


See link to shop ICT Billet Water Pump Spacers


LS Power Steering Pump Swap Guide

The power steering pump and pulley follow the same spacing principle. As you can see in the below guide the three pumps are noticeably different.

Keep in mind which power steering pump you have in conjunction with the rest of the accessory drive because pulley size comes in to play to make sure you have the correct length belt.

(-1) 1997-2013 Corvette spacing

(-2) 1998-2002 Camaro LS1 spacing

(-3) 1999+ Truck spacing

What this means to you?

ICT Billet uses these measurements to design our powersteering bracket kits. Understanding which powersteering pump you either have, or will need, will make your swap one step easier.

We do offer a kit with a power steering delete as well, so in the place of the power steering pulley we include an idler pulley and an updated belt length for that application.

Feel free to Contact Us if you have any questions, or refer to the guide below

See link to shop ICT Billet Power Steering Systems

LS Alternator Swap Guide

Do you know which alternator you have, or will need? The most common is the 105 amp alternator found on the truck engines. This alternator has the smallest casing and is what ICT Billet

has used to create most of the alternator relocation brackets. The biggest reason for needing an alternator relocation for a very tight fit in the engine compartment of the vehicle recieving the swap. Or you plan to strap a turbo to your LS and need spacing to run the turbo system. Whichever of the reasons you need ICT Billet alternator brackets will be able to take care of you.

What this means to you?

Wherever you need to mount your alternator ICT Billet brackets will be able to handle it. Keep in mind the size of the casing and where you want to put it, you can only use the smaller 105 casing if you are going to relocate to the passenger side head. The 145/160 casings are just to big.

Feel free to Contact Us if you have any questions!

See link to shop ICT Billet Alternator Brackets

LS A/C Compressor Swap Guide

Thinking of installing air conditioning on your swap? Most of our swap customers prefer to keep A/C on their vehicle. We make this easy by providing a wide selection of brackets to mount your A/C compressor on trucks, cars, hotrods, etc, with options ranging from GM factory R4, BMW, Ford, Sanden 508, 7176, 708, HT6 and other types of compressors. ICT Billet manufactures these brackets in house to our precise dimensions using GM specs for a perfect, reliable fit everytime.


block to clear the frame rails. The factory A/C compressor runs off a 4 rib belt off the back of the crank pulley, with our relocation brackets we are integrating the compressor into the serpentine belt system. This does change the compressor to a 6 rib pulley, which means you will either have to change the clutch and pulley on the compressor or purchase one of our compressors with a 6rib pulley.

What this means to you?

Integrating air conditioning to your swapped vehicle has never been easier. Pick from one of our many A/C compressor brackets is completely up to you, here at ICT Billet we want to make sure you have every combination of bracket you can think of, and get it to you quickly!

Feel free to Contact Us if you have any questions!

See link to shop ICT Billet A/C Brackets


LS Gen III vs Gen IV Swap Guide

Do you know which generation LS based engine you have? One of the most misunderstood components is identifying what engine block you actually have.

Even though most parts can interchange on LS Based engines, it is important to know the differences between a Generation 3 and Generation 4 LS engine.

There are many things that are different between these two generations of engines and can really be difficult to decipher what parts you need for your build.

Please refer to the guide below for a few visible differences between the Generation 3 and Generation 4 engines.

Feel free to Contact Us if you have any questions!


LS RPO Code Specs Swap Guide

What is a RPO code? This code is pretty much the DNA of your vehicle. These codes are what General Motors used as instructions to put together your vehicle back in the factory. The plant would see these codes and know which parts to include on the vehicle or which parts to leave off. Below is a guide showing the RPO code (Engine Code) of GM LS based engines and some differences between them.

What this means to you?

The RPO code is important to you because these codes will help you decipher what exact engine you have, how much power, and also, what parts you need to make it work in your swap. Not every LS based engine is a "corvette motor", as cool as that would be, the same parts that work on said corvette motor wouldnt work on other engines. So to save everyone involved a headache and delaying your build, its best to know what you have, and a game plan on the type of build you are wanting to do. Please review the guide below to check out the differences in the graph.

Feel free to Contact Us if you have any questions!


LS Crankshaft Swap Guide

Be careful when purchasing a flexplate and bolts. Reason why, there is a special year ('99-'00) 6.0L LS that had a "long" crankshaft. That means the crankshaft projects .55" inches from rear cover lip, compared to the .13" inches from the standard length crankshaft. This does not seem like alot of difference in measurement but it is the difference between your swap mating up or not. With the standard length crankshaft you need a dished flexplate & NO spacer. With the long crankshaft you need a flat crankshaft & NO spacer. The spacers are for non-LS transmissions.

What this means to you?

Mating whatever transmission you are using to your LS engine can be a very simple process or a very difficult one. Making sure you have all of the parts you need for your exact application will save you a ton of hassle. A common swap is a 6.0L LS based engine, for their power and reliability, but in the '99-'00 they came with a "long crankshaft". That long crankshaft will only work with a flat flexplate compared to the dished plate on standard length crankshafts. Just do your research on the engine you have, try and get the RPO code for your engine, or the VIN (Vehicle Identification Number) off of your donor vehicle and any GM dealership would be able to provide you with a build sheet which would have all of that information on it. Please refer to the guide below to see the differences and the ICT Billet parts needed

Feel free to Contact Us if you have any questions!

See link to shop ICT Billet Flexplates

LS Intake Ports Swap Guide

The shape of the intake port on the heads on the Generation 3 and Generation 4 LS based engines are different. The Generation 3 heads have a "cathedral" port. The Generation have a "rectangle" port. The difference between these heads are simple, the amount of cfm the heads can flow determine how efficient they are and how much power they can handle. The port of the head must also match the shape of the intake for proper air flow. The LS7 & LSX heads have a different bolt pattern which make their heads and intakes not so interchangeable with the rest of the LS family. The bolt holes are raised on the LS7 & LSX blocks compared to the lower bolt holes on the Gen 3 & 4 heads.

What this means to you?

We get alot of phone calls asking if a LS7 intake will bolt onto a LS3 head because they received a killer deal on an LS7 FAST intake. Unfortunately it will not fit due to the bolt holes not being in the same location, nor the port angle and shape. Be sure to take a look at the port of your heads as well. In the below LS intake manifold guide we were sure to include all of the possible LS engine RPO (Engine code) codes possible. Example: the LS1 has a cathedral port head, compared to the LS3, which has a rectangle port head. Here at ICT Billet we make adapters that will allow fitment of various LS cylinder heads to a variety of intake manifolds.

Feel free to Contact Us if you have any questions!

See link to shop ICT Billet Intake Adapters

LS Ignition Coils Swap Guide

Ignition coils are pretty straight forward. They provide the spark to your spark plugs by a signal from your Engine Control Module (ECM). From General motors the ignition coils are located on the valve covers. ICT Billet makes a coil relocation set that will allow you to more those coils to a remote location and clean up the top end of the engine.

What this means to you?

Being able to relocate your ignition coils will open up the top side of the engine for things like our ICT Billet Valve Covers! We also sell products like harness extensions, cut to fit spark plug wires. We make the relocation process as painless and universal as possible. The first thing you need to know is which ignition coils you have, or will need for your swap. Refer to the guide below to identify your coils.

Feel free to Contact Us if you have any questions!

See link to shop ICT Billet Ignition Coils

LS Fuel Injectors Swap Guide

Which fuel injector do you want to use with your swap? Do you know? What type of fueling do you need? Something simple, or a high flow application? Whichever need you have for fueling ICT Billet creates spacers and harness adapters that allow you to use pretty much any combination you can think of. Keep in mind not every injector is the correct height, or size to fit in any intake and fuel rail. See the below guide to get a better understanding of that injectors can fit where.

What this means to you?

What this means to you, is that your option for a factory style LS based fuel injector can now interchange into your intake and fuel rail combination. Example; you can now use LS3 injectors on your LS1, LS2, and LS truck intakes! This comes in handy when you have an application that needs a little more fueling but you do not want to spend a thousand bucks on some injectors. We also sell the harness adapters that allow the injectors a simple plug and play functionality, no need to worry about splicing and soldering wires. We are seeing a growing number of LS2 intakes swapped onto a truck motor, well with our adapters we can now use a LS truck injector to either an LS1 or LS2 intake! Very easy, clean installation. All of the hard work has been done, just install o-rings, set in rails, bolt together and tune!

Feel free to Contact Us if you have any questions!

See link to shop ICT Billet Injector Adapters

LS Throttle Body Swap Guide

Different generations of LS based engines came with different styles of throttle body. They got better in time and more efficient and easier to tune. Some have an IAC (idle air control) valve in the throttle body itself that controls idle airflow. The newer blades do not, they control idle airflow by just tipping the blade to a commanded point.

What this means to you?

This means that you have multiple options on the throttle body for your application. The earlier models are a three bolt type, meaning they bolt to the intake only using three bolts. The newer generation throttle bodies are 4 bolt. Different vehicle also have different size throttle bodies, and many aftermarket companies sell even bigger throttle bodies like the 102 mm. ICT Billet makes all kinds of adapters to make pretty much any throttle body work with your application. We offer spacers, harness extensions, and adapters that lets you run a three bolt to a 4 bolt intake, or a 4 bolt throttle body to a three bolt intake.

Feel free to Contact Us if you have any questions!

See link to shop ICT Billet Throttle Body Accessories

LS Supercharger Swap Guide

Plan to strap an awesome LSA blower on top of your LS engine? ICT Billet makes a LSA supercharger swap kit that will integrate the blower into a 6rib serpentine system. This kit is designed for truck spacing, only way to make it work with how far the pulley sticks out. We also make other pieces that will make that swap easier!

What this means to you?

This means that ICT has gone through the legwork of testing the LSA swap. Our goal is to make things as simple and universal as possible. There LSA blower on the ZL1 camaro has front facing water ports, while the LSA blower off the CTS-V has rear facing water ports, keep that in mind when you are planning your swap. Internally they are the same, same displacement, everything. Alot of customers opt to have the snouts ported by machine shops and pick up some good horsepower with them!

Feel free to Contact Us if you have any questions!


See link to shop ICT Billet LSA Accessories

LS Torque Specs Swap Guide

Below in this guide are the torque specs of LS based engines. These are the stock bolt torque specs, if you are running ARP bolts then refer to the instructions that came with the bolts for their torque specs. The column to the right on the guide shows a "degree" section, this means the bolts that are being used in that application are Torque To Yield (TTY). TTY bolts are one time use only becuase they stretch after they have been torqued. These bolts allow more clamping force when two metals are expanding and contracting, the bolt will move with it instead of fighting against and potentinally breaking.

What this means to you?

This means this guide is a one stop shop to give you common questions on the torque specs of these bolts. No more just sending her home with two ugga ugga's. Be smart. These engines are making a ton of horsepower on stock bottom ends, but its the small things that will allow them to keep being efficent and reliable for you. Please refer to the guide below for the torque specs!

Feel free to Contact Us if you have any questions!

See link to shop ICT Billet Bolt Kits


LS Oil Pan Swap Guide

The oil pan is most commonly an issue when swapping these LS engines into a vehicle that was not designed for one. Reason being, the clearance and the way the front suspension systems were designed are different. We have seen customers do many things in this situation, you can opt for a new modern front suspension system, or you can notch out what you need to to make it work. The guide below will show you some key differences and also measurements on the LS based engine oil pans!

What this means to you?

This means a LS engine will probably not drop right into your 72 C10 without some sort of front suspension work. Most common is to switch to some sort of k-member and mustang 2 front suspension system, that will make your swap steer like a modern vehicle as well as ride like one. ICT makes many accessories for oil pans. Please see guide below and get some good information and hopefully help you make a decision on which oil pan you would like to use in your swap.

Feel free to Contact Us if you have any questions!

See link to shop ICT Billet Oil Pan Accessories

LS Wire Connectors Swap Guide

LS Wiring Guide (Gen III DBC) Swap Guide

Did you recieve a big bulky wiring harness with your engine? Usually the answer is yes. Now there is nothing wrong with that, but usually we see customers wanting to hide as much wiring as possible. There are options for stand alone harnesses that were made for this exact issue, and they are pricey. There are MANY things that you will not be using in that harness. Things like ABS, traction control, theft deterrent systems, electronic brake control module, ect. will not be used. Below is a wiring guide that gives you the location of the wires that you have to have to make your engine run. This guide is for Gen. 3 engines, there could be differences with the Gen. 4 engines.

What this means to you?

This means that you can thin out that mess of a wiring bundle you have. Will make for a cleaner install. But most importantly will make it easier to diagnose a concern if you have an electrical issue. The less wires to worry about the better. These LS engines, are very particular to wiring, and voltage. Make sure to not cut corners when it comes to the electrical system. The modules are very sensitive to voltage, any fluctuation in voltage can cause them to do some very weird things. So take your time, refer to the guide and let us help you be great.

Feel free to Contact Us if you have any questions!

See link to shop ICT Billet Harness Accessories

LS Fittings Swap Guide

During your swap you may notice your need to make things work together that you did not think of before. Using fittings will allow you to do that, either a remote water pump, a turbo feed and return line, or even transmission cooler lines, engine oil cooler lines, ect. The list goes on. These fitting can make your world alot easier and they look pretty cool too. There are different sizes of fittings all tailored to your needs. There are also different thread types, and some have o-rings, some dont. There are fittings that go on the ends of hoses, or some get threaded onto fuel lines. See the guide below to take a look at the differences in fittings and how they can work in your application.

What this means to you?

Getting all of the components of your swap to work together is sometime tough. The factory fuel lines are not very universal, they are made exactly to fit the vehicle they are in. So how will you get fuel to your engine? You can get you some -8 fuel line, and a few 8an fittings and make it happen. Utilizing these different types of fittings will make your swap go easier and also become very reliable.

Feel free to Contact Us if you have any questions!

See link to shop ICT Billet Fittings and Accessories