Can A Modern V6 Swap Work? We Check Out Holley's LV1 V6-Swapped Pontiac Development Test Vehicle


Can A Modern V6 Swap Work? We Check Out Holley's LV1 V6-Swapped Pontiac Development Test Vehicle


The mere suggestion of willfully placing V6 under the hood of a project car is enough to cause many gearheads to flinch. The V8 soundtrack has been the backbeat to many projects over the years. How do you turn your back on decades of small-block Chevrolets, big-block Mopars, howling Coyotes, and the LS brigade? Why would you remove performance potential? Don’t you know that there is no replacement for displacement?

Holley Pontiac LeMans front high

Welcome to the modern age. This is the land of 300 horsepower four-cylinders with a factory warranty. As sexy as a rowdy V8-powered beast is…and don’t get us wrong, that is sexy…what are you really planning to do with your project that’s on the jackstands? We suspect that you’ll want to cruise it around. We bet that you’d love to take it onto something like Power Tour. You’ll want to see the sights. You’ll want to cruise around. And maybe, just maybe, you’ll run it down the dragstrip here and there and maybe an autocross lap here and there. But you’d be happy if you had something turn-key, daily-driver capable. And if you could have a bit of fuel economy, you wouldn’t be mad.

So why, then, would you shy away from a V6? Did you forget the magic that Buick made in the 1980s with turbocharged T-Types and Grand Nationals? Ever read the old reviews on the Pontiac Trans Am Turbos that came out for 1989? GM turned out plenty of potent V6s for the pickings. But maybe you don’t want to play with an engine whose architecture dates back to 1962…what then? We have your answer: the GM LV1 and LV3 V6.

GM's LV1 and LV3 V6 Engine

GM LV3 4.3L V6

The only things that the current GM EcoTec3 4.3L V6 shares with the previous small-block Chevrolet-based 4.3L V6 engine are the displacement, a 2-valve pushrod design, a 90-degree cylinder angle, and 4.4-inch bore centers. Heavily based on the Gen-V LT engine’s design, the two engines (LV3 has Active Fuel Management, LV1 does not) were phased into production for the Chevrolet Silverado/GMC Sierra pickup trucks and the Chevrolet Express/GMC Savana vans. Available in the trucks from 2014-2021 and available in the vans from 2018-present, the LV1/LV3 are all-aluminum, direct-injected units that bring 285 horsepower and 305 ft/lbs of torque to the table naturally aspirated, and 297 horsepower and 330 lb-ft. of torque when tuned for E85 operation from the factory. To put those numbers in perspective, a 1997 Chevrolet Camaro Z28’s LT-1 cranked out 285 horsepower and 325 lb-ft. of torque. For our engineering mule, we wanted a rear-wheel-drive car that had strong aftermarket support and a large fanbase. We also wanted the V6 swap to seem like a natural evolution instead of “look at what we replaced the V8 with”. And we wanted the swap to bring in a substantial increase in power over whatever was in the engine bay.

Why Should You Consider The LV1/LV3 Engine?

Holley Pontiac LeMans engine bay

There are two reasons to consider the LV1/LV3. The first reason sits before you: in stock form, this engine makes for a fantastic cruiser powerplant. There’s nothing but benefits over a decrepit 231 V6 or a wheezing 301 Pontiac: good, useable power all-around on a more efficient engine. If you wanted to put together a Malibu wagon for a family hot rod you’d road-trip often, you’re set. You have handling, you have brakes, and you have a small engine that’s outperforming a smogger V8 with ease. In a truck that has a curb weight around 5,000 pounds, you can see up to mid-20s MPG. In a car that weighs in somewhere just north of 3,000 pounds and with significantly less frontal area, do you think that 30+ MPG for the hot rod is worth it? You’re having your cake and eating it too.

Now…with that said, there’s a lot of you that won’t be satisfied with just 285 horsepower. Let’s look back to those mid-1980s Buicks for a moment. What made them special? What made them legends? We’ll spell it out for you: B-O-O-S-T. Turbocharged or supercharged, the Buick 3.8 loves pressure, just like the older 4.3L V6, as any Syclone/Typhoon fan will be quick to tell you. Add boost to an engine that shares a lot of components with a Gen-V 5.3L V8…see where we are going with this? The folks at Scoggin-Dickey Parts Center did and their dyno mule LV3 has made as much as 644 horsepower and 730 ft-lb. of torque with their “Stage 2” camshaft, 14.5 PSI of boost and VP MS109 fuel. Your imagination can certainly figure out what to do with that kind of power, right?

SDPC Turbocharged LV3 Dyno Test - 644 Horsepower, 730 ft-lb. Torque!

Our Development Mule: 1979 Pontiac LeMans

Holley Pontiac LeMans studio front 3/4

First introduced as a sporty trim package on the 1961 Tempest, the LeMans became its own, separate model for Pontiac in 1963 and made the jump from the compact Y-body to the intermediate A-body in 1964, where it would stay until 1983. After a brief hiatus, the LeMans name returned on a Daewoo-built subcompact loosely based on the Opel Kadett E. Our particular test mule is a 1979 example, a fifth-gen car that rides the same A-body platform that underpinned the Chevrolet Malibu, Buick Century and Pontiac Grand Am and is almost identical to the better-known G-body platform that GM sold through the 1980s. While you can see the scars of time on the car if you look, the LeMans is still in remarkable condition considering the age of the car. With good bones to work with, it was a matter of improving upon what was already there to keep up with the power increase the LV3 swap.

Why start with a G-body? Because it is a meeting point for several ideals: this is a body-on-frame intermediate, which harkens back to the original Musclecar Era, but it’s also a car from the lowest of the low points of the Malaise Era. The shape is undeniably early 1980s, but from just before horsepower started to come back and you got into the tech-and-laser weirdness. It has plenty of room inside for four adults, but it still feels smaller and nimble, especially in this day and age of the pickup truck and the sport-utility vehicle. And there is a NASCAR tie-in: Bobby Allison and Tim Richmond used the sleeker LeMans instead of the notchback Grand Prix when NASCAR required teams to move to a 110-inch wheelbase.

When we got the keys to the LeMans, we were informed that tuning was still ongoing...that meant that we were limited to driving it like we were running to the store for groceries, not as a performance vehicle. Not ideal, given the low stance, six-speed shifter and the impressive exhaust note. But when you're allowed to drive an engineering mule, you live under the engineer's rules. Everything about the Pontiac feels like a proper, well-kept late 1970s vehicle, so long as you ignore said shifter (the car was originally a column-shifted automatic) and the Edge Insight CTS3 covering the gauge port where the clock would've been that is providing engine data. Insert the key with the door open and you'll be reminded of a time when the key-in buzzer wasn't so soothing and calming. Twist the key to the "on" position, and a second buzzer angrily reminds you to fasten your seat belt. There is no drama to starting the LV1...clutch in, twist the key and it fires right off as a modern engine should. After a brief warm-up, we dropped the car into first and rolled out.

First impressions are great. The LeMans is tight, the steering startlingly crisp. You've never driven any late 1970s GM product that feels like this. The LV1 pulls nicely around town...anything over 2,500 RPM is for your enjoyment and nothing more. The T56 is a sweetheart of a transmission and the gears are nicely spaced. The only thing that we wish we could've seen was what the full rev range was like...but again, we were on our best behavior, cruising around with the windows down, listening to the surprisingly solid bass notes of a larger V6. You want livable power? This is what it looks like.

The front suspension is composed of a Detroit Speed Front Speed Kit 1, which brings in tubular upper and lower control arms, Bilstein shocks, 2-inch drop coil springs, chassis bracing and a Detroit Speed sway bar. Out back is more Detroit Speed-sourced goodness in the form of a Rear Speed Kit 2, which features replacement control arms with Detroit Speed’s Swivel-Link ends, a tubular sway bar, replacement coils and Bilstein shocks. Compare that to even the nicest stock G-body you can find and you’ll notice that a significant amount of sponginess is gone. The hydraulic clutch has good feel without being a knee-killer and the brakes outshine just about anything offered on a GM product in the 1980s save for maybe a Callaway Corvette or a 1LE Camaro. Considering the work that is still needed, the LeMans is smooth and sweet. Roll the windows down and enjoy the drive as you "click-click" through the T-56's six gears.

What Is In The Future?

Holley Pontiac LeMans rear

As said before, our LeMans is simply a development mule. Some parts that were used to swap the LV1 under the hood might be seen on Holley for sale soon, while others are still being tested and evaluated. Whether you want a slick driver-quality hot rod or want to bring on the modern-day equivalent to a chipped and tuned Grand National engine, that’s up to you. What we want to know is would you actually build something like this? We’re not talking about theoretical builds, either. We want to know if you’d actually consider the LV1/LV3 V6 as an alternative to an LS or LT engine swap. How would you build it, and what parts and tuning capability would you like to see for sale on Holley? In addition to G-body vehicles, we could easily see the LV1/LV3 finding homes in S-trucks, third-gen F-bodies, and maybe even lighter-duty C10s and C1500s. We've even know of a DeLorean DMC-12 that has an LV3 in the engine bay. What would you consider shoving this engine into? Follow Holley on either Facebook or Instagram and let us know!

Holley's 1979 Pontiac LeMans LV1 Swap Development Mule - Parts

EngineGM LV1 V6 (4.3L, 262ci), modified Gen-V LT swap oil pan, Holley Gen-V LT Mid-Mount Accessory Drive, custom intake manifold, Holley DBW pedal and bracket
TransmissionTremec T-56 Magnum, hydraulic clutch pedal conversion
ExhaustModified Holley Gen-V LT exhaust manifolds, Flowmaster universal catalytic converters, Hooker BlackHeart G-body exhaust kit
Fuel SystemHolley G-body fuel tank, fuel filter/regulator
Engine MonitorEdge Insight CTS3
DriveshaftInland Empire
WheelsRocket Racing "Attack"


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