Project BluePrint Chevelle: Swapping An LSX Into An A-body Chevelle


For the last several months, we’ve been teasing about our ultimate Chevy project car being on the donor list awaiting its very special LSX engine from our friends at BluePrint Engines. Luckily, the 1964 Chevelle, appropriately named Project BluePrint, is now finally ready for the process we’ve all been waiting for. So it’s out with the old and in with the new (engine that is), as well as a couple other system upgrades. Installation of a new fuel system, Billet Specialties front belt drive, MSD ignition, Hedman swap headers and mounts, Flowmaster exhaust, AEM gauges and a top-off of Royal Purple oil were also prescribed by the motor doctor.

Swapping a BBC engine for a built LSX is an exciting but intricate process, so along the way, we’ll be giving you some tips and tricks we learned to help fellow enthusiasts taking on a similar swap conquer their own projects. And of course, we’ll also be addressing clearance issues, fitment solutions and the no-pain no-gain attitude of full automotive rebuilds as we dive deeper into one of our most intensive projects yet. So strap on those harness belts and hold on tight, because this ride is about to get crazy!

IMG_8735What We’re Working With

When we first came across our 1964 Chevelle, it was a no-brainer buy. Great sheet metal, relatively new paint and excellent bright work on the car gave us the unique opportunity to focus solely on the mechanics of our soon-to-be pro-touring beast while not worrying about the aesthetics that would eventually be on display.

Under the hood, the Chevelle came to us with a mild 468ci big-block engine, surely an upgrade from the stock 283ci or 327ci small-block options the car came with from the factory. It was still not exactly as crazy as we wanted, even with the addition of long tube headers and an aluminum radiator. So we contacted our friends over at BluePrint Engines to talk LSX. But before the new engine went into the car, we had to get rid of the old plant and that’s where the dirty work in the Power Automedia shop was required.

Installing a slimmer, longer and taller modern LS engine into the 1st generation Chevelle was going to take some finesse and massaging. 

Installing a taller, longer and slimmer engine was going to take some finesse to stuff it under the hood of our A-body.

The Tear Down

Tearing out an engine is only the beginning of a fantastic build, but it might also be one of the most important parts of the process. Not only do you have to get the old engine out to make way for the car’s new power plant, you also have to make sure that components, like engine mounts and brackets, are salvaged if the build requires in order to reduce time and money used in the swap.

We pulled out the big-block and all the hardware in preparation for our engine swap.

For our project, we didn’t salvage much as far as the old engine was concerned, especially since many components won’t transfer from a BBC application to an LSX build. But as our shop manager, Sean Goude points out, it’s best to label any salvageable parts, including wiring from your previous engine if you plan on using them for your future application.

Things to Consider When Doing an LSX Swap


  • Engine Size: How much time, fabrication and money are you willing expend to make an engine fit?
  • Transmission: What’s the intended use and space available?
  • Supporting Components: Crossmembers, motor mounts, and brackets must be taken into consideration as part of the swap plan.
  • Exhaust: When swapping in an engine, headers meant specifically for your application and swap make life much easier.
  • Fitment: When it comes right down to it, PLANNING is the ultimate key to having a successful engine swap.  
  • Oil Pans: Not only do you have to choose a pan based on your engine’s needs, you’ll also need to scope them out for clearance issues.
  • Be realistic: We’ve all had dreams of 1,000+hp cars at one point in our lives but when it comes to building, make sure you don’t bite off more than you can chew. 

Because we didn’t need to salvage anything, the tear out of our BBC was pretty straight forward. After yanking the wiring, unbolting our mounts and brackets, and properly securing our big-block to an engine hoist, we were able to release the engine from its internal confines. And because we opted to tie our BluePrint engine to our Gearstar transmission before swapping in the new mill, as you saw in our recent BluePrint update, we also stripped the transmission from the Chevelle’s grasp.

With a bare engine bay, tracking down clearance issues, possible fitment problems and areas that would need some extra consideration was our next goal. Luckily, with the compact package of modern LS engines, built or otherwise, fitting the BluePrint engine into our GM A-body didn’t present much of an issue, especially with all the aftermarket components out there for projects like this. We were able to create a more compact overall package with things like the front drive assembly and headers to further our ease of dropping in the new LSX.

The Top Things To Consider When Doing An LSX Swap

When swapping any engine for another, it’s important to consider things like intended use, intended power output, possible drivetrain combinations, how your engine is going to be fueled and how you’re going to make everything you need to have your car running in tip-top shape to fit in the confines of your engine bay. Here are our top 10 keys to having success with an LS engine swap.

Engine Size: The question should never be will a certain engine fit in a certain car. The question should actually be how much time, fabrication and money are you willing expend to make an engine fit. You can shoehorn just about anything into any engine bay with enough time, fabrication skills and wallet cheddar. For those of us on a limited schedule and budget, taking a close look at the engine dimensions of the original and the replacement engine can minimize the trouble areas.

Here’s an example of the size differential: the standard SBC engine that was manufactured from 1958 to the 1990s measured 25.40-inches wide at the widest point, and was 22-inches tall from valve cover to the bottom of the oil pan. The SBC 350 was 29.42-inches long from water pulley to the flywheel.  By comparison, an LS1/LS6 engine is slightly skinnier (24.75-inches), a little longer (29.75-inches) and much taller (28.25-inches). The 6-inch taller LS engine may cause fitment issues under the hood so make sure you make your engine choice accordingly.

Taking out the old engine mounts and replacing them with a set of mounts a little lower on the crossmember helps keep the engine under the hood.

Engine placement is also an important factor. GM used a 4-degree tilt down at the rear of the engine with the rear axle pinion shaft centerline at the same angle except up in small-block Chevy engines. For street use, most builders will suggest the crankshaft centerline to be 3-4 degrees down at the rear. For drag racing application the rear axle pinion shaft centerline will be in a downward angle to compensate for rear axle rotation under hard acceleration.

Engine tilt can be checked by placing a level on the carb mounting surface of the intake. Level the engine from front to rear and side to side. This will give you the correct inclination for the engine.


Our weapon of choice for transmissions was the Gearstar level 4, 4L65E transmission package.

Transmission: To decide on an optimal transmission for your engine, keep in mind the intended use and space available to put it under your car. Transmission tunnels can be modified and completely rebuilt if the fitment issue is in this area, but length and proper position of the transmission aren’t as easily modified. Bolt pattern is also key to pay attention to.

LS engines will work with any older GM trans with some considerations. TH350s/ 700R4s/ TH400s work by using a GM flexplate spacer and bolts to place the flexplate at the proper spacing. This provides a place for the converter snout to engage. The thing to consider is the downshift/ TV cables. There are many companies that have pieces to make them work. Obviously the 6-speed manual T-56 or automatic 4l60Es designed to be behind the LS-engines work easily with the proper harnesses.

Our combination included a Gearstar level 4,  4L60E Automatic transmission package. The placement and size of the transmission requires a bit of fabrication on the tranny tunneling inside the car. Basic welding skills and a few hand metal working tools is all that is needed to fab up a new tunnel that supports the larger tranny.

Our 5 degree engine tilt and 4L60E Gearstar's transmission required some tunnel fabrication.

Once again, size plays an important roll in selecting transmissions. Let’s say that you want to use the popular T-56 transmission with your LS engine. Not all T-56 transmissions are the same size. The CTS-V series has a noticeable gear selector lever set-back of more than 3 inches over the 1999-2002 Camaro version of the T-56. The GTO and SSR versions fall in between these two for size. Know what you are getting and what the dimensions are when you are putting together your plan.

A sheet of mild rolled steel, basic welding skills and a ball peen hammer is all that is needed to fab up a decent tranny tunnel.

Supporting Components: Deciding how you’re going to support your drivetrain is key to any build project. Crossmembers, as well as motor mounts and brackets must be taken into serious consideration so that they not only support the weight of your drivetrain and keep it in place, but also that these components will fit easily but snuggly in the correct factory positions. Keep in mind that engine tilt and size may necessitate the need to move engine mounts to a different location. In our case, we had to move the engine mounts back and down from the factory original location.


Don’t forget to consider your supporting components like engine mounts (pictured here – Hedman Part #03815). Not only do they need to support the engine weight and torque, but they may even need to relocate the engine in the engine bay.

There are a great number of companies that specialize in making components for LS engine swaps now. Attempting to list them all would be insanity, but rest assured, you get what you pay for with conversion kits. The inexpensive kits will probably require more “massaging” to get them to work.


Purchase headers meant specifically for your application and swap choice.

Exhaust: Pulling extra heat and spent fumes from your engine is important for optimal performance, and let’s face it, that iconic musclecar sound. When it comes to swapping in a different engine than what your vehicle came with, be sure to purchase headers meant specifically for your application and swap choice. This will not only ensure clearance around steering and supporting components, it will also allow for more power from your build.

Much like the adapter kits mentioned above, exhaust systems seem to have a quality to cost relationship. Anyone with a mandrel bender can bend exhaust tubes, but the companies that put in the research and development are the exhaust systems that produce more power, have less fitment issues and frankly, just sound better. We optioned Hedman Hedders LS swap (Part #45216) knowing that we wanted great performance and a perfect fit right out of the box. The other option is to have an exhaust system custom-built for your swap, which generally blows the idea of a budget build right out the window.

Front Drive: Whether you’re building a daily driver or an all-out track beast, having a proper fitting front drive is vital. With kits from companies like Billet Specialties, you can get all your pulleys and belts to fit within tight quarters. Stock ones can be used for budget builds or by choice, but may need some modifications depending on how it sits in your car.

Specialized front drive kits, like this one from Billet Specialties, are a bolt on addition that handles all the horsepower that you want to throw at it.

Serpentine belt front drive systems are the most popular and will handle all the horsepower you can throw at them without tossing a belt under naturally aspirated conditions. If you plan on installing large power adders and forced induction, or when pulley synchronization needs to be precise, you may need to step into a gilmer belt drive.  

Moving on to the front drive system, we turned to well-known Billet Specialties for a Top Mount Tru Trac Serpentine System kit specifically made for LS motors (part # 13455/13475). This front drive system is engineered to clear cross members and steering boxes used in most musclecars while keeping a low profile tight against the engine block.

Billet also offers front drive systems for comparable A-body Chevelles with an added AC compressor pulley, if chilled temperature control is a must for your personal project.

Fitment: Nothing is worse than concocting a killer build in your head and then not having everything fit properly once you dive into the project. When it comes down to it, PLANNING is the ultimate key to having a successful engine swap. Measure twice and order once.

We chose a very stock-like wet sump oil pan that provided plenty of clearance at the cross member.

We chose a very stock-like wet sump oil pan that provided plenty of clearance at the cross member.

Oil Pans: Not only do you have to choose a pan based on your engine’s needs, you’ll also need to scope them out for clearance issues and interference with things like engine mounts and cross members. Oil is the life blood of your engine and its pan deserves to be treated as such.

Wet sump oil systems are more common, less expensive and there is a lot of aftermarket support. The flip side is that the wet sump oil pans are larger and require more space because of the sump area. Decide early in the planning process if you are going with a wet sump or dry sump oil system.

IMG_1601Generational Differences: When working with LS motors, you’ll find Gen III and Gen IV versions. Pay close attention to which generation engine you’re running and match it to the proper engine controller in order for the engine to work. Gen III LS engines were built between 1997-2007 where the Gen IV engines range from 2005 to present day.

The Gen IV LS engines were designed with displacement on demand in mind, a technology that allows every other cylinder in the firing order to be deactivated. It can also accommodate variable valve timing. Most Gen IV engines are throttle by wire throttle bodies and have electronics to operate them. You must use the accelerator pedal and TAC module to make them work properly.

Ask Questions: Whether it’s on a forum, tech line or to your buddies, ask questions if you get stuck. There’s no point in forcing components together only to find out later that they don’t work, you broke something, or could have accomplished your goal a lot easier.

Be Realistic: We’ve all had dreams of 1,000+hp cars at one point in our lives but when it comes to building, make sure you don’t bite off more than you can chew. The more power you’re looking to push, the more money, time and research will need to go into the car.


Engine Installation and Upgrades Galore

With the old engine yanked, wires pulled and support components removed, we were looking at a very bare engine bay. The old engine was a carbureted fuel system which didn’t require a lot of electrical engine management and as luck would have it, our new Blueprint built LS engine would also be carbureted.

IMG_1953The biggest concern when mounting these LS engines into an older GM chassis is having the engine sitting as close to where the old block sat as possible. Chevy engines run on the four-degree rule. That is, the engine usually sits on a four-degree downward angle from front to back. The four degrees is recommended to help with your pinion angle and other important drivetrain functions.

The actual mounting of the transmission to the crossmember could’t be easier. It may be necessary to use a universal crossmember from an aftermarket source. Usually the driveshaft will have to be shortened and this is an area where you will have to rely on the professionals. Just for the record, different shops measure for driveshafts in different ways, so call ahead any time you have to shorten or lengthen a driveshaft. After the engine is solidly mounted in place, you can start working on adding all the accessories and upgrades.

Selecting MSD's 6LS ignition module was a no-brainer. It allows us to grow with different fuel delivery systems without replacing the ignition system.

Selecting MSD’s 6LS ignition module was a no-brainer. It allows us to grow with different fuel delivery systems without replacing the ignition system.

One of the few wires and electrical boxes that we had to plumb into the system was an ignition system. Starting with the MSD ignition, we opted for the 6LS-2 Ignition Controller for LS applications (part #6012). Not only does this controller offer a direct plug-and-play installation, it also gave us the option of upgrading our engine to fuel injection later on without having to change this component. The MSD 6LS-2 also offers a programmable two-step rev limiter, vacuum advance curve and step retard, giving us everything we need to optimize our engine’s spark.


To get the fuel flowing to our BluePrint engine, we looked at several different options before deciding on AED’s HO Series 850cfm carburetor (part # 850HO). Budget-friendly but mighty stout, this carburetor gave us everything we were looking for, from a clean idle to crisp throttle response.

There is no point in replacing your car’s engine with a built one if it’s not going to respond at the snap of a finger. That’s why finding an ultra-responsive carb that also gives you impressive acceleration and a clean idle is absolutely necessary.

Adding Fuel to The Fire

Continuing on with our fuel system, we turned to Holley Performance to set us up with a whole gamut of components, from a billet fuel filter (part # 162-555) to all our fittings, tubing, and seals.

Adding to our fuel system parts, we also secured a RobbMc ½ inch sending unit with an optional -8 AM fitting already attached. This drop-in unit features a billet aluminum base and lines, and provides a more budget-friendly option then fuel cells.

We turned to FAST for our remaining fuel system needs and used a FAST inline fuel pressure regulator (part # 307030). Made with CNC-machined billet aluminum, FAST’s fully adjustable fuel pressure regulators offer twin -6 feed side ports as well as a single -6 return port on the bottom of the unit for optimal efficiency.

We added a low-pressure Holley electric fuel pump inline to replace the previous engine’s mechanical fuel pump. We knew that we would be upgrading to electronic fuel injection soon, so the low-pressure pump was a temporary component in our system.

Holley Performance's line of billet components were our choice for fuel delivery.

While we initially planned on using all AEM gauges in BluePrint, we went ahead and switched some of the gauges out for Dakota Digital’s VHX Series components. However, we did stick with AEM when it came to our air/fuel gauge. For reliable readings in an easy to install package, we opted to go with AEM’s Wideband Air/Fuel Gauge (part # 30-5130). Not only does this gauge give us unprecedented accuracy, speed and control for our air/fuel readings, it also provides us needed tuning information in an easy-to-read analog interface that clearly indicates even a half a point change in our air/fuel ratio.


Having a proper air/fuel ratio is pertinent for preventing engine damage and maintaining optimal engine performance and with the AEM air/fuel gauge we can see if our BluePrint Chevelle is even slightly off at any given time. This allows us to catch any damage or performance hindrance before it becomes an issue no matter if we’re on the track or cruising the street.

Dakota Digital's VHX Series gauges replaced the stock gauges with a serious upgrade in performance and looks.

Wanting more breathing room for our BluePrint 427ci engine, we looked to Flowmaster for a perfect header-back exhaust system to tie to our Heddman long tube headers. With the perfect combination of modern and muscle, Flowmaster set us up with their American Thunder dual exhaust system specifically made for 60s A-body Chevelles with V-8 engines (part # 17202).

In the past, securing an exhaust system for an LS swap project was challenging and at times even required custom bent or retrofit headers and other exhaust components. Now, however, with swap friendly setups like the Hedman LS swap headers and engine mounts, having the perfect exhaust system for your LS classic is a breeze.

A true upgrade from the old pipes, our Hedman Hedders and Flowmaster Exhaust is just what the musclecar doctor ordered.

The Flowmaster American Thunder exhaust system offers our LSX Chevelle two Super 40 Series mufflers, 3-inch aluminized steel exhaust tubing, and dual side exits. Not only does this give our GM A-body a fierce aesthetic, it also gives it an aggressive exhaust note that no musclecar, classic or modernly prepared, would be complete without.


Hedman Hedders are designed to hug the LS block and fit nicely in this cramped area.

Controlling the Transmission

In the process of upgrading our Chevelle’s engine, we also wanted to upgrade the car’s transmission. For this we chose Gearstar’s Level 4, 4L65E transmission package as described earlier. To control this bad boy, we got ourselves an HGM Compushift II transmission controller with AccuLinks TPS, specifically geared toward carbureted applications. This controller allows you to change shift points, as well as control the torque converter clutch lock-up for a unique and defined driving experience.

Compushift II transmission controllers are available for both EFI and carbureted engines.

HGM Compushift II transmission controller with AccuLinks TPS, specifically geared toward carbureted applications.

Choosing the correct controller for your application will make a world of difference depending on how your car is fed. Installation is simply a plug and play type wiring harness with very little mechanical aptitude needed.

With all the harnesses necessary to install our new device and a handheld display included with our Compushift II controller, our Gearstar combination is purring perfectly along with all our other performance upgrades. What’s even better is we were able to accomplish this without ever having to hook the controller up to a laptop.

Since we upgraded the transmission and tied our Gearstar to a Compushift II transmission controller, we also upgraded our Chevelle’s shifter. For this, we chose a B&M Pro Stick Shifter with an aluminum cover (part # 80706).


We capped off our upgrades with B&M’s Pro Stick Shifter.

This cable-operated shifter offers spring-loaded gate action and a one-hand reverse lockout in a compact and stylish package. It also features the ability to be used with a variety of transmissions if we ever choose to fit our BluePrint Chevelle with a different gearbox, although we don’t see that happening in the near future.

To top off all our performance goodies, we got our hands on plenty of quarts of Royal Purple oil, but we’ll get into that in Part 2 as we take a deeper look at what all our BluePrint engine has to offer, how the engine build and install went and what kind of performance numbers we saw with the swap. Stay tuned for all the final details as we wrap up our Project BluePrint build!


About the author

Lindsey Fisher

Lindsey is a freelance writer and lover of anything with a rumble. Hot rods, muscle cars, motorcycles - she's owned and driven it all. When she's not busy writing about them, she's out in her garage wrenching away. Who doesn't love a tech-savy gal that knows her way around a garage?
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