LS-Engine Swap: Here Are The Install Parts You’ll Need

Let’s just say that swapping an LS engine into a classic Chevrolet is nothing new. There have been guys doing it for a few years. But, we still get questions from time to time asking us about what parts are needed to actually complete the swap. There is no doubt that the swap can be very time and patience-consuming, so we are going to show you guys where to get the parts, and who makes them.

There is a lot of information available on the subject, so we will cover as much as we can in a fairly comprehensive two-part article. This month, we will show you what engine and transmission mounts, headers, and accessory drives you will need for your swap. In our next installment, we will cover the required fuel system(s), cooling, and ignition sources.

ls swap

The A-body Chevelle makes a great recipient of an LS swap.

All of the parts that we highlight, have been designed and manufactured by companies that spend countless hours, and invest a lot of money to make the parts you need so that they are available to do the swap. You could probably fabricate your own mounts and design your own ignition-control system, and you might even save some money in the process, but is that really an attainable task?

Why spend your weekend trying to make parts that are already available? Check out our list, and find out for yourself how easy it can be to install an LS engine into your classic Chevy.

Engine Mounts

Once you have the old engine, wiring, and the other ancillary items ripped out of the way, you now have an engine bay that is ready for a new-or new-to-you-LS engine. But, before you begin, the first thing you need to do is to figure out how you are going to mount your LS.

Mounting an LS into a classic Chevy requires both the engine-mount plates (left), and the engine mounts (right).

When installing any engine into any car, paying close attention to driveline angles and engine positioning is critical. You might not realize it, but if you fabricate your own mounts and then just throw the engine in place, there is a very good possibility of the angles being incorrect. Try driving the car down the road and you will likely rattle your teeth right out of your head when you finally get the car up to speed. Check out a video here about driveline angles.

Find Your Engine

It wasn’t that long ago that not many people understood the LS engine, and what versions were available in what cars. We remedied that problem with an article dedicated to that very subject. Check out; LS Engine Article

Since the original engine in your classic Chevy is designed to run at a 3- to 4-degree down angle (the front of the engine is 3 to 4 degrees higher than the rear of the engine), retaining this proper angle is not only recommended, it is crucial in order to keep your pinion angles/drivetrain operating smoothly. This is a very good reason to get pre-engineered mounts for the swap instead of trying to make something work.

Luckily, there are different companies that have taken the time, and used the resources, to develop and offer engine mounts and mounting kits to help enthusiasts swap an LS engine into their classic. The hard part is deciding which company you want to use. The choice is entirely up to you, but we have had good luck with UMI Performance, Hooker, and Speedtech Performance. Getting a quality set of mounts designed for your application will definitely make the swap a lot easier.

UMI Performance

UMI Performance has kits to mount LS engines into most classic Chevys: Camaros, Chevelles, and Novas to name a few. This kit shown is PN 4008, and allows the installation of LS power into your 1968 to 1972 GM A-body. UmiUMI’s LS mount places the engine in the factory location, but it also gives you the ability to relocate the engine rearward up to ¾-inch, or forward ¼-inch. UMI’s LS-engine mounts will bolt directly to your car’s frame and the LS block without modifications. Their LS mounting brackets have greasable polyurethane mounts to dampen vibration but still provide a solid feel. These included polyurethane mounts eliminate the need to locate additional engine bushings/mounts.

Note: UMI’s LS mounts were built using the LS1 oil pan. If using an aftermarket oil pan, some crossmember trimming may be needed. Also, when using certain factory front-accessory drives, the A/C compressor might come into contact with the frame and require minor frame clearancing.

Speedtech parts

Speedtech Performance

If you are looking for a complete LS engine swap mounting kit, Speedtech Performance eliminates the hassle of looking for the individual parts you need. They deliver a package of high-quality, LS swap parts that are made in the U.S., and are designed to work together.

Their virtually complete LS engine swap kit brings together just about all of the needed pieces that are designed to install an LS engine between your factory frame rails. The parts in the kit include a sheetmetal oil pan, the billet engine-mount relocation plates, polyurethane engine mounts, frame-mount stands, and a custom-bent set of 1 3/4-inch primary tube stainless steel long-tube headers. Speedtech tells us that their headers will clear both factory style and rack and pinion steering, and the oil pan clears crossmembers on Camaros, Chevelles, and Novas.


Hooker not only makes headers for just about any make car, but they also make engine mounts, These LS swap mounts are designed to make swapping an LS engine into your classic muscle car or truck as easy as possible. With five different mount kits available, you are sure to find the mounts that you need so you can position the engine and transmission in the proper location. Holley MountsThese mounting plates are available for use with stock small-block Chevy engine mounts; that means you can place the engine and transmission in the stock location or move it forward 1/2, 1 1/4, or 3 inches. Hooker also offers a mount kit designed for applications that use the clamshell type mount like those in the G-body.


Since an LS engine was never thought of when many classic Chevy’s were built, the factory manifolds are probably not going to work. That being said, the stock Gen III/IV exhaust manifolds are quite capable of working with an engine supplying 400 to 500 hp.


LS1 in a Chevelle frame with long-tube headers.

The trick is finding a pair that will fit your chassis-good luck. The engine mounts and the manner of their installation usually determines if there is exhaust manifold compatibility.

For that reason, headers are your best option when installing an LS engine. The typical headers that will work for your LS are usually a long-tube header with a 1 3/4-inch primary tube, and a three-inch collector.

Hooker Headers

Hooker Headers currently gives you a choice when it comes to LS-swap headers. Available in either traditional metallic-ceramic coating or the newest offering that they call Darksides ceramic coating. 2276-7hkrThe headers are available in various designs to fit everything from Tri-Five Chevys and Camaros to Chevelles. Hooker’s headers are a long-tube design, and with their ceramic coatings, exhaust heat goes out the back of your car, not under the hood. Their traditional metallic-ceramic coatings are good for up to 1,300 degrees, and the Darksides can withstand temperatures up to 1,700 degrees. These coatings on the headers make either of these an excellent choice for your car.


When it comes to supplying exhaust systems, Flowmaster Mufflers has what they call their Scavenger Series Elite headers. These headers are designed to fit LS swaps in 1967 to 1969 Camaros, Chevy IIs, and even the later Nova. For you A-body guys, they even have them for the 1964 to 1972 Chevelle as well. The headers come with a long-lasting ceramic coating and have the benefit of 1 3/4-inch primary tubes and 3-inch collectors. The collectors feature a ball-flange socket to connect to the exhaust, which Flowmaster LS headercreates a virtually leak-proof connection. With the ball-and-flange connection, you never need to worry about blowing out a gasket. The full-length header is designed for a precise fit and will deliver increased performance over factory manifolds. We do have to let you know that unfortunately, these headers have not passed C.A.R.B. testing. That means that they are not emissions legal, and are designed for off-road use only.


12 may 10 clutch

Speedtech crossmember installed.

After retrofitting the LS engine into the engine compartment of your classic, the next step is figuring out how to support the transmission. When swapping an LS with a late-model transmission into a classic Chevy, an aftermarket crossmember is usually required. With that being said, we have heard that some people were able to use the stock crossmember simply by sliding it back on the frame rails and redrilling the frame-mounting holes. If you are able to do this to your application, don’t forget that the driveline angles will need to be checked. If you are not comfortable with that scenario, like we said, there are companies that offer bolt-in crossmembers for classic Chevys.


While Hooker does make a transmission swap crossmember, they tell us that it is designed to work with their engine-mounting components. But, it does fit with any of the following transmissions: 4L60, 4L80, Turbo 400, 2004R, and the Tremec T56.12644hkr It’s made of heavy-duty welded steel and provides the correct engine/transmission angle that is critical to U-joint working angles when installed with Hooker engine mounts. It also provides enough clearance when using exhaust pipes of up to three inches in diameter.

Speedtech Performance

If you decide to get your transmission crossmember from Speedtech Performance, they would like you to know that they are engineered to be fully adjustable. This means that they can be moved forward or rearward in the vehicle. Speedtech designed their crossmember with this feature so that the end-user can accommodate a myriad of engine positions, and even make use of a Tremec T56 transmission.

SpeedtechThe Speedtech crossmember is designed and built using a small diameter bar that is strong enough to hold your transmission in place, yet still allow ample room for more exhaust clearance than other versions. So, you can use that larger three-inch exhaust that you have been planning to install. What’s more, is that the crossmember is built with an added feature so that it can be removed independently from the brackets mounted to the vehicle. With these available options of already built, bolt-in crossmembers so readily available to you, why would you even consider trying to make one yourself?

Oil Pan

You have probably heard horror stories about oil pan clearance issues when sliding an LS engine into a muscle car. Typically, a factory pan will need to be modified to work, but why bother? There are manufacturers making a bolt-on pan that works.


While Holley is typically associated with fuel delivery, they are just as committed to guys swapping LS engines into their cars. Holley oil panThe Holley LS Retrofit Oil Pan is designed in the traditional rear-sump arrangement. That means crossmember clearance should not be an issue. According to Bill Tichenor at Holley, “We designed it for maximum ground and chassis clearance.” Since the pan is made of heavy-duty cast aluminum, it retains the strength and sealing capabilities of an LS factory oil pan. It comes as a six-quart capacity, and includes the proper oil pickup and pan baffling to take advantage of the new pan’s shape. It also retains the oil filter and cooler-port locations and is designed to use the factory gaskets.


MorosoThe LS swap pan from Moroso features integrated baffling for oil control, an angled sump, and is a fabricated steel unit. The pan has a capacity of seven-quarts and is six-inches deep. Don’t worry though, it is designed not to hang too far below the crossmember of your car. The Moroso pan is designed to fit 1967 to 1992 Camaro, 1968 to 1978 Nova, 1965 to 1972 Chevelle, 1953 to 1996 Corvette, and the 1978 to 1988 G-body. This pan is also compatible with longer-stroke crankshafts (4.125 inches). It comes with a billet aluminum adapter that accepts either a Moroso oil filter (PN 22462) or an OE filter located in the stock location.

Front Drive

The three most commonly used “factory” front-accessory drive systems that are installed when swapping an LS engine into a classic Chevy are usually the factory Gen IV Camaro, C5 Corvette, and the Vortec truck.

Since the factory A/C compressor mounts on the lower passenger side, it usually hits the frame. On the driver’s side, the power steering pump and alternator can also cause clearance issues. Luckily, there are companies making front-drive kits that will solve the problem.

Billet Specialties copy

Billet Specialties

One choice when looking for an LS-specific front-accessory drive system is Billet Specialties. Their kit features what they aptly named their Top Mount System. The Top-Mount LS kit makes installation of the LS engine easy. The ease of installation is because the Top-Drive kit is engineered so that the A/C compressor is relocated up from the factory location in order to clear crossmembers and steering boxes in most muscle cars. This is an all-inclusive kit that delivers everything you will need for the installation. It comes with needed items like a new ATI crankshaft damper, an all-new Edelbrock LS water pump, and other quality components like a Sanden air conditioning compressor and a Powermaster alternator. One small thing we need to make sure you understand is that this kit is not compatible with engines that have VVT (Variable Valve Timing) technology. However, we hear that they are working on rectifying that situation.

Concept One

The compact design of the Concept One Victory LS accessory drive solves the problem of interference between classic car crossmembers/frames and the factory A/C compressor. The complete kit comes with all the standard equipment needed for installation, which means a perfect fit. Because of this, there is no need to source other parts. It is an easy install, which makes it perfect for the do-it-yourselfer.

Concept One

The Victory kit is designed to fit all Gen III and Gen IV LS style engines; even those with VVT. The kit will accommodate most popular throttle bodies, including LS1, LS2, LS3, and cable-driven applications like aftermarket brands.


Holley has been building fuel system components for almost as long as there have been cars on the road. They have proven that when they undertake a project, they do it right–and as economically as possible. One thing you might not expect to see from Holley is complete front-of-engine accessory-drive kits that include everything you will need for installation on the front of your LS engine. They even include the belt. What you find when you open the box are all accessories, pulleys, a tensioner, and the belt that are all manufactured by OE part suppliers. Most of these parts were used on LS engines from the factory, so you know they will fit. Holley drive

Until Next Time

Now that we have covered the actual engine-mounting parts needed for the install, we suggest that you tune in next time when we go even deeper into the install. In our next installment, we will show you what ancillary parts (fuel delivery, ignition, and cooling) are needed, and where to get them to make your new LS engine swap in your classic Chevy run like that new engine should.

Article Sources

About the author

Randy Bolig

Randy Bolig has been working on cars and has been involved in the hobby ever since he bought his first car when he was only 14 years old. His passion for performance got him noticed by many locals, and he began helping them modify their vehicles.
Read My Articles

Hardcore Chevys in your Inbox.

Build your own custom newsletter with the content you love from Chevy Hardcore, directly to your inbox, absolutely FREE!

Free WordPress Themes

We will safeguard your e-mail and only send content you request.

Chevy Hardcore - The #1 Performance Bowtie Online Magazine

We'll send you the most interesting Chevy Hardcore articles, news, car features, and videos every week.

Chevy Hardcore - The #1 Performance Bowtie Online Magazine


We will safeguard your e-mail and only send content you request.

Chevy Hardcore - The #1 Performance Bowtie Online Magazine

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...

Hot Rods & Muscle Cars

Drag Racing

Engine Tech

Chevy Hardcore - The #1 Performance Bowtie Online Magazine

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...

  • Hot Rods & Muscle Cars
  • Drag Racing
  • Engine Tech

Chevy Hardcore - The #1 Performance Bowtie Online Magazine

Thank you for your subscription.

Thank you for your subscription.

Chevy Hardcore - The #1 Performance Bowtie Online Magazine

Thank you for your subscription.

Thank you for your subscription.