The Rarest Buick Engine Ever Produced

Buick’s engines can be found all over the world; they’ve been modified for use in the Indianapolis 500, British sports cars, and any number of trucks, SUVs, and luxury cars that you won’t find at any Buick dealership. We can split hairs about which Buick engine was actually produced in the lowest numbers, but if we’re talking a Buick engine in a Buick car, specifically a production Buick car, then that’s probably the 231cid V6 packed into the Buick GNX.

Technically speaking, the rarest Buick engine ever made might be the Buick/Menard V6 that powered the Lola T93/00 and Lola T95/00 from 1993 to 1996, but that engine crashed out in Las Vegas after a troubled racing season. We’re here to track down the rarest Buick engines you can actually go out there and find on the auction block if you know where to look. That hunt starts with the GNX.

Only 547 1987 Buick GNX Units Were Produced

The 1987 Buick GNX debuted as part of that model year’s Buick Regal lineup, the Buick Regal being a car we wish they’d bring back. The GNX (Grand National Experimental) hit the market at a premium cost of $29,900, or about $83,000 today, adjusting for inflation. Hagerty puts a used model in good condition at $109,000, so if you were able to snag one when these were new, you could be sitting on a tidy little profit of around twenty-six grand before taxes.

When the car hit the track, it actually managed to outrun the Ferrari F40 and the Porsche 930 over the quarter mile. Nicknamed “Darth Vader’s Car” or the “Dark Side Grand National” for its sleek, black appearance with sharp lines (and the fact that Star Wars was pretty big in the 1980s), the GNX was only offered for a single model year, producing just 547 units. Or rather, 547 units plus the GNX #001, the 1986 prototype, which still belongs to Buick, and which they bring out to car shows now and then.

The #001 has mainly served as a promotional tool and as a living museum piece. Back when the car launched, they used to take car reporters for a ride in this prototype.

Buick still makes the car available to automotive journalists from time to time, but it reportedly only puts about ten extra miles on the odometer every year, mainly from carting it in and out of storage to get to various car shows.

A Look Under the Hood of the 1987 Buick GNX

Buick GNX V6 Engine Specs

The Buick GNX’s base LD5 engine was not the rarest of the bunch. In fact, the 231 cubic inch motor had been available to the public since 1978, powering the front-wheel drive Buick Riviera. Even the turbocharged version of this engine had already made its way into the 1976 pace car for the Indianapolis 500, and a production turbo model was launched shortly thereafter.

What set the GNX’s potent V6 apart would be a handful of factory-installed modifications that we can confidently say make this, for all intents and purposes, a new engine designed specifically for the GNX.

Upgrades That Make The GNX’s 3.8-Liter Turbo V6 Unique

• A ceramic Garrett AiResearch T-3 turbocharger
• Upgraded Garrett intercooler with ceramic-aluminum pipe
• Low restriction exhaust system
• Revised programming for the Hydramatic 200-4R transmission system

In previous Buicks, the LD5 had produced around 100-160 horsepower. In the GNX, that number was cranked all the way up to 300. They might not have rebuilt the entire engine block, but that’s a number you weren’t going to achieve with any other LD5 V6. The car was underrated in promotional material at a horsepower of 276, with further testing revealing another 24 horses under the hood.

Being such a scarce automobile, it stands to reason that a handful of myths have persisted about the 1987 Buick GNX. One such myth claims that it’s a twin-turbo. It’s not, it just packs a really innovative turbocharger for its time. The car has also been reported to have been based directly on the turbocharged Indy 500 pace car.

The turbocharged V6 in the GNX is essentially a whole new build with no real overlap with the Indy 500’s engine. Both of them used a Garrett intercooler, but the one found in the GNX looks nothing like the one packed into the pace car.

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The TVR Power Rover 4.5 V8: The Rarest Buick Engine In A Non-Buick Car

The Rover 4.5 was actually a 4.4-liter V8 built for the 1988-1989 TVR 450 SEAC, a car that saw a production run of just 17 units plus the prototype. Supposedly, more than 18 of these cars actually exist, though, as buyers who couldn’t get their hands on a 450 would buy a roughly comparable TVR Wedge, and then convert it to 450 SEAC spec. The engine was also packed into a handful of race cars, as well as some TVR Chimaeras and Griffiths.

Exact production numbers are unknown, but there certainly weren’t too many 4.5s made beyond the 18 produced for the 450 SEACs.

TVR Power Rover 4.5 V8 Engine Specs

To bring the body weight down as much as possible, the 450 SEAC used an innovative mix of fiberglass and kevlar body panels. The Ferrari F40, released just a year prior, used a mix of kevlar, aluminum, and carbon fiber in its body panels. The 450 SEAC’s unique blend of fiberglass and kevlar may have been an industry first.

The 3.9-Liter TVR Power Rover V8: The Rarest Non-Street Legal Buick Engine

TVR produced more of the 3.9-liter TVR Power Rover V8s than they did the 4.5-liter engines, adding up to around 100 units in total. But, the 1984-1985 TVR 390SE that carried these engines under the hood was never made street legal. Or at least, not while it was still in production.

During the car’s initial run, it was never granted British Type Approval, meaning it couldn’t legally be driven on British streets. Without British Type Approval, it wasn’t approved for import in most countries, either.

3.9-Liter TVR Power Rover V8 Engine Specs

Today, you can legally buy a 390SE and drive it around wherever you like, as the 25-year import rule is up. But when the car first hit the market, it wasn’t street legal, so we’re going to have to say this is one of those rare engines that never made it to mass production.

Adding up every TVR Power Rover V8 ever produced between the 450 and the 390SE, they made these in much smaller numbers than the GNX’s turbocharged V6, but if we’re calling it the rarest Buick engine ever made, that’s got to be something packed into a Buick car, not just based on Buick components.

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The Buick GNX Is The Ultimate Not-Quite-Mass-Production ’80s Car

The fact that the 1987 Buick GNX never resulted in its own nameplate, and the fact that they never brought it back, means that it lived up to its name, the Grand National Experimental. Whether Buick thought there was limited interest in a high-performance Regal, or street-legality was a complicating factor, or they just wanted to make sure that the GNX remained a special, one-off piece of American automotive history, we’re glad it exists.

While the car may have been too rare to have ever become an icon of the American highway in the 1980s, the very concept of a turbocharged V6 Buick Regal feels very eighties. This was the era that came after the energy crisis and saw Americans falling in love with high-speed, high-power vehicles all over again, and when you add that Darth Vader helmet profile to the mix, you’ve got the ultimate 1980s car that never really went into mass production. And for the record, Killer Mike does own a Grand National, but it’s not a GNX.

Sources: Automobile Catalog, Hagerty, Buick, TVR