If you’ve been following along with the updates on our ’71 Nova, named project “Swinger,” you saw the wheel tubs and frame connectors we installed, along with the body repairs we did. In that same article, we hinted at the new powerplant we were dropping between the frame rails, and in this installment we’ll reveal our sinister plan to update our Nova with a thoroughly modern small block Chevy – the supercharged LSA, with a little help in the oil pan department from RetroLSX.

The LSA vs. the LS9

When it comes to power and performance in the LS family, the LSA is second only to the LS9. Derived from that Corvette ZR1 powerplant, the LSA first appeared in the 2009 Cadillac CTS-V and made its way from there to the GM Performance Parts catalog. The LSA pumps out 556 horsepower with 551 pound-feet of torque. Now, if the LSA and LS9 are so similar, you might be asking why anyone would choose the LSA. “The LSA is perhaps the best bargain in our entire catalog: it sells for around $12,000 and cranks out 556 horsepower,” explains Dr. Jamie Meyer, head of Product Integration for GM Performance Parts. “Now, the LS9 has the titanium rods, forged pistons, bigger blower, and a ZR1 pedigree that you can’t top. But, if you are looking for an engine that will give you a supercharged street cred and rock the socks off the competition, the LSA has to be on your shopping list.”

We test-fit the LSA in our Nova without the blower to make it a little lighter and easier to maneuver.

While the LS9 and LSA share the same block, internally and externally they part ways. The LSA utilizes a smaller 1.9L Eaton supercharger in place of the LS9’s 2.3L. Inside you’ll find cast hypereutectic pistons instead of forged (and a slightly lower 9.1:1 compression ratio), and powdered metal connecting rods substitute for the titanium ones that you would find in the LS9.

1.9L Eaton Supercharger & Intercooler

GM has a long and successful partnership with Eaton, and the LSA supercharger draws from years of experience developing blowers that are powerful, quiet, and take less power to operate. With the 1.9L (and its larger 2.3L sibling on the LS9), Eaton went from a three-lobe design to the present four-lobe rotors with 160 degrees of twist.

When we asked Dr. Meyer what his favorite aspect of the LSA was, he replied, “Blowers are cool. Roots blowers, from the factory, with all of the GM Powertrain development time baked in are just plain awesome. Unlike a turbo that takes a little while to get cookin’, the Roots blowers provide you with instant pleasure. These Roots-blown engines touch something deep within you. They scare you. They make you feel alive. There’s that nasty, high-pitched squeal that starts building under the hood when you get into it. It’s like you’ve touched off a bomb, and it takes about 1 nanosecond for the fuse to hit the dynamite.”

The Eaton 1.9L supercharger is one of the main keys to the LSA's performance capabilities.

Because the Cadillac CTS-V is not pressed with clearance issues under the hood, the intercooler on the LSA is able to use a single-unit heat exchanger versus the dual heat exchanger on the LS9. This heat exchanger is slightly taller than that on the LS9, but it provides better airflow.

One place that the LSA beats the LS9 is in the intercooler department - the LSA uses a taller single core unit rather than the dual core intercooler necessitated by the Corvette's low hood.

LSA spec sheet

• Gen. IV 376 c.i (6.2L) small block with a 4.06” bore
• Forged steel crankshaft with a 3.42” stroke
• 6600 RPM Redline
• Hypereutectic aluminum pistons with integrated piston cooling oil jets
• Conventional wet sump oil system
• Aluminum L92 style port heads with a 9.1:1 compression ratio
• Hydraulic roller camshaft with .480-inch intake/exhaust valve lift

This cutaway illustration of the LSA shows (among other things) the 160 degree twist of the blower rotors.

Mounting the LSA

To mate the LSA to our Nova, we went the “work smarter, not harder” route and used BRP Hot Rods’ LS Swap Kit. The kit came with the engine brackets, frame mounts, crossmember, transmission mount, and all of the hardware necessary to make the swap easy

BRP Hot Rods' motor mounts make putting an LS block into an older Chevy a bolt-in process.

RetroLSX Oil Pan

With the 18X11-inch Forgeline wheels and 275/40/18 tires we will be using, keeping the stock power steering was not in the future for this Nova. Installing the Steeroids Rack and Pinion Conversion Kit will help the driver by reducing the amount of energy it takes to turn the wheels, but thanks to the Nova’s rear-steer design that places the steering linkages behind the front wheels, clearance was going to be tight. In order to avoid having to raise the engine in the car (and end up with a higher center of gravity and hood clearance issues as a result), we decided to go the opposite route and find a pan that was thin enough to clear the power rack.

The RetroLSX oil pan allows us to use the new Steeroids steering rack with room to spare.

Of course, there’s more to getting the right pan than whether or not it will physically fit in the car. Since we’re going to be throwing the Nova around pretty good between the cones, we wanted to make sure we’d have sufficient capacity and good baffling, so the oil pump won’t end up sucking wind. Despite being a slender 5.5 inches deep, the RetroLSX pan maintains a full 5 quart capacity, as well as good slosh control.

The RetroLSX oil pan is a custom-cast design but it is based off of the LH8 design, which has great oil control. RetroLSX doesn’t include the LH8 windage tray, but it fits perfectly if you’re switching over. Combined with the sump design and pan baffle, we’re confident that the pickup will stay covered while the crank isn’t, no matter how hard we throw this car around. The pan does come with a pickup tube, pan baffle, drain plug, cooler cover, and gasket, so all you’ll need is the aforementioned LH8 windage tray to complete the package.

Though the RetroLSX is based on the LH8 pan, it's considerably slimmer, improving ground clearance as well as making room for the steering rack.

The LSA is an incredible high-tech powerplant, and thanks RetroLSX, dropping it into our Nova was as easy as a run-of-the-mill 350 SBC. We’re one step closer to putting 556 supercharged GMPP ponies to the ground, so keep an eye out for future installments as Project Swinger nears completion.