How to Swap an LSA Crate Engine into a C1 to C4 Corvette

Having 825 horsepower loaded into your C1 to C4 Corvette is just an engine swap away. That’s how much our Chevrolet Performance LSA crate engine made on the SAM Tech dyno using a Comp cam and a battery of bolt-ons; that’s right, no stroker and no ported heads. Imagine bolt-ons and a cam with pump gas. With that kind of capability, we are just itching to drop this into something. If you are, too, then keep reading. We are going to take a look at what it takes to install one in an older Corvette. I know what you are thinking, “It’s just another LS engine.” Well, not so much. Armed with the knowledge you see here can save you from a number of headaches.

Will It Fit?

No doubt the first question on any Corvette enthusiasts mind is: will it fit my Vette? Believe it or not, the only two applications that it will not fit are the C5 and C6. Though these two have factory LS engines, they use a particular accessory drive system that tucks up tightly to the front of the engine to clear the power steering and other items not compatible with the LSA. In essence, the only way to use an LSA engine would be to swap out the supercharger for an LS9 or aftermarket blower. At that rate, there may be other options that make more sense than using a crate engine only to start tearing it apart. (At the same rate, if you find a good deal on a take-out long-block, swap away with the C5/C6 supercharger of your choice.) The appeal of the LSA engine is that you can have a plug-and-play 580 horsepower for even less money than the 505-horse LS7, let alone the 638hp LS9, both of which are dry-sump; adding an even greater level of complexity.

According to Pace Performance, the LSA engine measures: 30.15 inches from the bottom of the oil pan sump to the top of the supercharger lid, and 29.13 inches from the flexplate to the front of the accessory drive system. For comparison, an LQ4 from a truck measures 28.25 inches tall and 28.75 inches front to back. With a Corvette intake manifold, oil pan and accessory drive it works out to be 27.5 inches tall and deep. Depending upon how high or low you mount the engine, you will need to make sure that it clears the hood and anything mounted along the firewall. (Note: the lid on the CTS-V’s LSA is different than the ZL1 version that Chevrolet Performance sells now, which will change the firewall clearance a bit. If the depth of the oil pan is a concern, you can replace it with any LS oil pan; more on this below.)

Common LS Parts

The good news is that there’re quite a few commonalities between the 6.2L supercharged LSA and its naturally aspirated brethren. For example, it is still a wet-sump engine that can use any of your favorite oil pans like Holley’s popular swap pans (PN 302-1, 302-2). The motor mounts are the same as any LS engine so your typical swap conversion mounts will work. Whenever possible you will want the conversion mounts to be application specific and matched to a transmission crossmember that accommodates your chosen slushbox. If you were thinking about using an aftermarket frame, then you can just have it built to fit without any conversion parts needed. Some will even provide mounts for several applications. First generation along with midyear and C3s will need an LS conversion radiator with an electric fan. The C4 radiators can be made to work with LS engines. Most large Corvette parts retailers such as Corvette Central have these parts in the catalog. For the exhaust system there are quite a few options. Ultimate Headers and Stainless Works offer headers specific to midyear and C3 LS swaps, while American Racing’s headers fit only the C3. Melrose is perhaps the only company offering LS swap headers for the C4. The other option is to try a variety of stock manifolds, from the LSA’s stainless steel set that face straight down or a C5/C6’s cast set that are angled back. Too many companies to mention offer aftermarket shorties and block huggers that you can also try.

Air Intake

The off-centered and angled entry to the supercharger makes the air intake unique to the LSA. A 3.5-inch pipe is a close match to the LSA’s throttle body, requiring just a simple coupler and clamps. Trial and error can help establish whether something ready-made will fit your application. If something custom is required, or just preferred, a good fabricator can weld up a custom aluminum intake pipe with a high-flow filter and a proper mount for the MAF sensor. Airaid is one of a few manufacturers that have DIY kits as well.

EFI

As we discovered on the dyno, aftermarket EFI certainly has its advantages. However, a factory system is not without one huge advantage as well, and they are called knock sensors. Positive displacement superchargers are like large heat sinks, so having a system that monitors detonation and dials back timing in an instant is useful. Regardless of which you decide, the LSA crate engine comes from Chevrolet Performance with a 58x reluctor wheel, 4x camshaft timing gear and electronic throttle, so you will need a wiring harness and ECU that accommodates both; otherwise you’ll have to start swapping out parts and inventing a number of complicated solutions. The easiest solution is to purchase Chevrolet Performance’s controller kit (PN 19354336), which includes a wiring harness, E67 ECM, MAF sensor, O2 sensors and even an electronic accelerator pedal. A stock crate engine requires no tuning, while a modified LSA (like ours) can be handled by any quality calibrator.

Heat Exchanger & Pump

The LSA crate engine does not come with a heat exchanger or coolant pump, as we mentioned in Part 1 of the series, to aid the air-to-water intercooler. Among the available coolant pumps, the factory ZL1 (not the CTS-V) is an excellent performer in flow and pressure. The ZR1 is the best OEM option and costs nearly four times as much as the $255 ZL1 pump. However, there are options that sit somewhere between the two that perform as well or better than both. There are quite a few heat exchangers on the market, both application-specific to the CTS-V and ZL1 as well as universal. Depending upon where and how you would like to mount it, each has a different appeal. The Weapon X Motorsports low-mount CTS-V intercoolers are great for smaller grille openings, measuring 36 (wide) x 7 (tall) inches. If you can afford the space, AFCO has a massive 26 1/4x11 1/8-inch heat exchanger that is available with dual 10-inch SPAL electric fans. The optional black thermal coating actually increases the cooling. If none of these work head over to Summit Racing. While the CTS-V and ZL1 did not come from the factory with an overflow/expansion tank for the intercooler, that is also a worthy investment.

Pulleys

The accessory drive system is the big one. The spacing is similar to the Camaro SS and trucks, which is much farther away from the engine than the C5 and C6. And obviously the routing, orientation and tensioners needed for the supercharger make it completely unique. There is a dedicated eight-rib drive for the supercharger itself, a separate six-rib drive for the power steering and alternator, and a third belt for just the A/C compressor. The basic Chevrolet Performance kit will fit most applications so long as you want power steering and no A/C. The add-on A/C bracket sticks out way too far for most applications. The simple solution is the Kwik Performance A/C bracket and compact Sanden compressor, which keeps the factory belt routing but tucks the compressor tighter to the block. Concept One offers the only complete eight-rib kit to accommodate a variety of applications and accessories. This kit moves the A/C compressor up high away from the framerail and puts everything on a single eight-rib belt. Multiple finishes, power steering pumps and alternators are available. It has an SFI approved balancer and 3.0- or 2.55-inch supercharger pulley, and looks amazing.

Fuel System

While no different than any other EFI LS engine, which operates at 58 psi of fuel pressure, an LSA engine will require a substantial quantity of fuel. The stock ZL1 pump flows 250 lph at 65 psi and is a pulse-width modulated unit with its own controller built in. Thankfully, companies such as Tanks Inc., and Rick’s Tanks make complete fuel tank solutions that include high-flowing OE fuel pumps. Rick’s even offers tanks for 1956-’82 Corvette model years with ZL1 and CTS-V pumps with a controller. If you plan to run E85, step up to a 380-lph or higher pump that is ethanol compatible. High-powered E85 setups will run twin 400-lph pumps with an LS9 fuel rail and a regulator to convert to a return style fuel system. Normally, the fuel feed line on the LSA faces straight back toward the firewall and uses the typical OE quick disconnect.

Driveline

Again, the powerful LSA engine requires some extra consideration that a naturally aspirated LS1 or LS3 does not. The demands are much higher for a transmission that will hold the supercharged mill’s low-end grunt. The ZL1/CTS-V’s 6L90E six-speed auto is an obvious choice. A 4L60E four-speed automatic can be built to hold up in a Corvette, but it would have to be something like PerformaBuilt’s Invincible Black Label transmission with all the fixings. A relatively stock 4L80E may be a cheaper option, if you don’t mind the loss of efficiency. Either four-speed requires a transmission controller and a wiring harness. If you plan to keep your trans old school, stick with a fresh Turbo 400. For those that prefer three pedals, a TREMEC Magnum T-56 is the natural choice as the aftermarket equivalent to the factory TR-6060 in the ZL1 and CTS-V.

At this power level a multi-disc converter or clutch is needed. When purchasing, take note of the LSA’s eight-bolt flange on the crankshaft. The attachment and spacing is different than a typical six-bolt LS flywheel or flexplate, which needs to be accounted for in the clutch or converter design. Aftermarket ZL1 and CTS-V clutches easily solve this issue with the use of a Magnum trans, and a custom converter will accomplish the same; allowing you to adjoin it to your slushbox of choice.

01.Since Corvettes can have difficulty fitting a big-block and tall intakes, the height of the supercharger is certainly a concern for retrofitting an LSA. However, the height is not insurmountable, particularly when using an aftermarket frame.

02.Factory oil pans typically hang too low or don’t clear the crossmember in swap applications, which is what makes Holley’s Retro-fit Engine Oil Pan ideal. It is cast and machined just like the OEM version, including the same oil filter mounting, oil cooler port and bellhousing attachment points. It comes with the sump baffle, pickup tube, sump plug, oil filter stud and oil passage cover for around $400. Carbon black, polished and cast finishes are available along with a version with additional front clearance.

03. If you are planning on using an aftermarket frame, the chassis builder can build in the correct mounts. However, for stock frames you will want to use conversion brackets. There are quite a few on the market. For example, Hooker offers three different versions of these swap brackets that place the engine 0.50, 1.25 or 3 inches forward for around $90. These 3/8-inch thick, hot rolled steel mounts are zinc plated and simply bolt up to any LS engine so that the factory three-bolt motor mounts can bolt to it. A separate version is available for late-model clamshells.

04. If you purchase an LSA crate engine it will come with these very nice stainless steel cast exhaust manifolds that point straight down and to the rear. Since we have not test-fit these we can’t say for sure, but they appear that they would fit most applications such as C3s where C5 manifolds are a common choice. On this engine, the manifolds are not much of a restriction in stock or near-stock form.

05. For those who love the sound of a lumpy cam, any set of LS swap headers will do. Though the port shape varies slightly, the flange is exactly the same on all OEM LS heads. If you check out Kooks offerings for the Camaro ZL1, you’ll notice that 1 7/8-inch primary headers are the smallest they offer. There’s a reason for that. You may be used to 1 5/8- or 1 3/4-inch headers on your small-block, but neither are preferred for this supercharged beast.

06. This is the basic cold-air intake kit that Chevrolet Performance offers (PN 19301246) for under $400 to match any of its LS crate engines with EFI. It is certainly functional, but depending upon your available space and taste, a custom-fabricated intake may be in order.

07.If you had already completed an LS swap and tried to bolt an LSA into your Corvette, you’d realize pretty quickly that PCV lines and sensor connections are quite a bit different. For one thing, both the LSA and LS9 have additional inputs and outputs to the ECM to account for forced induction that naturally aspirated LS engines do not (the intercooler pump and a second IAT sensor, for example).

08.The LSA uses GM’s E67 controller from the factory. It is easy to tell the difference between the more common E38 used with LS3 and LS7 crate engines because it has three plugs instead of two (as well as the boxy Gen III controllers). This was the fastest ECM of its day, with the most inputs/outputs. This is the reason GM chose it for forced induction and variable valve timing applications. Chevrolet Performance sells this as a full kit (PN 19354336) with the wiring harness, sensors and accelerator pedal.

09. The Eaton 1.9L supercharger has an air-to-water intercooler with an input and output port on the top of the lid facing the front of the car (on the ZL1 version). The factory uses two quick disconnects here along with rubber lines to run the coolant mixture. These can be (and often are) converted to AN fittings and braided line.

10. To circulate the coolant through the intercooler and heat exchanger, an electric pump is needed that does not come with the crate engine. Thankfully Weapon X Motorsports sells this upgrade to the factory CTS-V pump for under $300 that they say is very similar to the ZL1 pump. Notice the plug for the factory wiring harness.

11.The heat exchanger is the next item that must be addressed. Weapon X sells a Track Attack version that measures 21x16 1/2x2 1/2 inches with a 2 1/4-inch core. The theory is that the larger surface area and twin 1-inch tube core allows air to pass through at lower speeds and take advantage of the dual fans behind the radiator.

12. AFCO is another source for heat exchangers, making this 26 1/4x11 3/8-inch version for the ZL1. The width is 2 5/16 plus 2 1/16 inches for the dual 10-inch SPAL fans. It is a double-pass design with 350 percent better cooling than the OEM piece. The fans are ideal to keep the blower cool during low-speed driving. It comes with its own wiring harness and relay, but there’s also a version without fans that measures 3 inches wide (26 1/4x11 1/8).

13. Our crate engine came from Chevrolet Performance with the complete LSA accessory drive kit (PN 19243525). Normally, the LSA uses a dedicated eight-rib drive for the supercharger pulley, a six-rib for the power steering and alternator and a separate drive for the A/C compressor, which is mounted low on the passenger side (A/C is sold separately). In terms of belt wrap and traction, this setup is hard to beat and recommended for maximum reliability. However, the downside is that the A/C compressor often runs right into framerail.

14.Concept One takes a much different approach by utilizing a single eight-rib drive for the entire accessory drive. The A/C is placed high on the passenger side, and the entire system is much more compact (and better looking). Multiple finishes and options are available for various power steering pumps and alternators. This is a complete kit with a Sanden SD-7 style compressor, Delphi steering pump, Powermaster alternator and an SFI balancer (which is why it costs over $2,800).

15.The supercharged LSA requires quite a bit of fuel, so in addition to the usual baffled style EFI fuel tank from someone like Tanks Inc., we would suggest a minimum of 340 lph of flow from the pump.

16. The LSA has a unique fuel rail with a hard line feed that faces the firewall on the passenger side. In OEM form it uses a quick disconnect with a separate braided line that attaches to the hard lines that run the length of the chassis to a pulse-width modulated fuel pump (with no return line). Using an LS9 fuel rail or turning the LSA rail around can be used as the basis of a return style system with an aftermarket fuel pressure regulator on the driver side.

17.The LSA’s eight-bolt flexplate is spaced properly for a 6L90E automatic transmission and converter, not a Turbo 400 or even a 4L60E or 4L80E. With the correct converter pilot support, it can be made to fit a 4L80E style converter such as with Chevrolet Performance’s Connect & Cruise 4L80E kit.

18.If you have already invested in a nice torque converter and trans that you want to reuse, then check out TCI Automotive’s and Circle D’s flexplates. Otherwise, you’ll want to purchase a custom converter like this one from FTI Converters that will bolt up perfectly to the flexplate (notice the three bolt holes).

19. Given the grunt of the LSA, especially when modified, a 4L80E (or its three-speed father; the Turbo 400) are typically the drivetrain of choice. However, a 4L60E such as this Invincible Black Label model from PerformaBuilt can hold up just fine and are much more efficient. The only downside is cost. Your standard rebuild or Level 2 build isn’t going to cut it, which means you’ll need to open up your wallet for all the aftermarket upgrades. If the steep 3.06:1 First gear bothers you, PerformaBuilt has a fix for that as well.

20.For the three-pedal lovers, there are a few manufacturers such as Lingenfelter that make an eight-bolt flywheel and clutch combo for TR-6060 and T-56 based transmissions. This one uses a proprietary billet steel flywheel along with a factory GM Corvette ZR1 twin-disc pressure plate and clutch assembly. Depending upon the transmission and bellhousing, a different actuator/slave cylinder will be needed.

21.The TREMEC TR-6060 is the replacement for the T-56, which features a 31-spline output shaft, triple-cone synchros and beefier gears. Right out of the box, it has all the upgrades you need to hold up to an LSA. The location of the shifter, overall length and bellhousing are noticeable differences between the previous T-56, which will affect clutch selection and retrofits. You can use either a take-out from a Camaro or CTS-V (as shown), or you can purchase a TREMEC Magnum from a dealer like American Powertrain. The C6’s transaxle version will not work in a traditional arrangement.