For most enthusiasts who lived through the 1960s and 1970s, a muscle car had to be based on a large-volume production model and hide a large, potent, naturally aspirated V8 under the hood. While the limited-edition 20th Anniversary Trans Am ticked the first box, it came with a turbocharged V6.
No longer with us today, Pontiac was once one of the biggest names in the automotive industry, especially for those with an uncurable addiction to quick and ridiculously overpowered rides.
For the 1964 model year, the GM division responsible for delivering excitement on four wheels to the masses launched the GTO package for its Tempest LeMans intermediate.
Adding chassis improvements and, more importantly, a potent 389-ci (6.4-liter) V8 with either a single four-barrel carb or a trio of smaller two-barrels, the GTO was a factory-built godsent for the growing number of young and restless performance enthusiasts.
A marketing hit, the new model started a horsepower war that produced a large number of tire-shredding weapons in the years that followed.
A brief history of the Trans-Am
Photo: Mecum
The fast-paced growth of the factory-built performance market ignited by the GTO led manufacturers to start offering potent V8s in smaller packages, such as pony cars and compacts.
Pontiac joined the pony car party relatively late, launching the Firebird in 1967, but it wasted no time to offer a powerful V8, adding the GTO's 325-hp (gross) 400-ci (6.6-liter) powerhouse to its options list.
Still, the Firebird lacked a distinct trim/performance package that differentiated the standard version from the higher-performance one, mechanically and visually, like the Camaro's Super Sport (SS) or the Mustang's Bosses and Mach 1.
That changed mid-year in 1969 when the WS4 "Trans Am performance and appearance package" was introduced.
Named after the Trans-Am racing series, the package added several visual upgrades, including a rear spoiler and a distinct Cameo Ivory finish contrasted by twin Tyrol Blue stripes that ran from the bespoke hood's dual vents to the lip of the trunk lid.
Available only with the L74 Ram Air (often called Ram Air III) version of the 400-ci (6.6-liter) V8, the Trans Am was a veritable muscle car with 335 hp (gross) on tap.
The Trans Am returned in 1970 on the second-generation Firebird, and even though performance dropped after 1971, it continued to fly the muscle car flag even during the dreaded Malaise era.
In 1982, a completely redesigned Firebird was introduced, and while the high-performance trim remained available, it was still far from the performance levels that it once offered.
Celebrating 20 years of the Trans Am in style
Photo: Mecum
As the years went by, horsepower figures improved little by little, going past the 200 hp (net) mark in 1985 thanks to the addition of the LB9 Chevy small-block to the Trans Am's options list.
Nevertheless, the most impressive Trans Am of the 1980s was yet to come.
In 1989, the nameplate reached the 20-year milestone, and to celebrate the occasion, Pontiac was granted pace car duties for the 73rd running of the Indianapolis 500 race.
GM's excitement division didn't settle for celebrating 20 years of the Trans Am simply by pacing the famous race, so management decided to build a very special edition able to handle Indy 500 duties in bone stock form.
Even more impressive, Pontiac decided to make the epic 20th Anniversary Trans Am available to the public through a 1,500-unit production run.
Painted white with a contrasting tan interior, the limited-edition model looked like the regular T/A GTA it was based on, but the Turbo Trans Am badges on each front fender hinted at what made it unique.
Borrowing Buick's iconic turbocharged V6
Photo: Mecum
Though it wasn't the first Turbo Trans Am, the 20th Anniversary was lightyears ahead of its 1980-1981 forced-fed predecessor.
However, unlike the turbocharged second-generation Trans Am, the new model did not feature a V8. Without getting into the gist of things, the lack of two cylinders and the forced induction system might have angered some muscle car purists. Still, nobody had anything to complain about after reading the official specs and the reviews published by the nation's most esteemed car magazines.
As I mentioned earlier, Pontiac wanted to take on Indy 500 pace car duties in a stock Trans Am. Legend has it that the division's engineers initially wanted to develop an all-aluminum V8 for the 20th Anniversary model. However, that was deemed too costly and time-consuming, so they borrowed the most potent version of the 3.8-liter turbocharged V6 from GM stablemates Buick and coupled it with a four-speed 200-4R automatic.
Engineers soon discovered that the powerplant didn't exactly fit snuggly inside the third-generation Firebird's engine bay. To solve the issue, several modifications had to be made, and to save time, Pontiac contracted Van Nuys, California-based engineering specialty manufacturer Prototype Automotive Services (PAS), to help.
Working in close coordination with the division's engineers, the PAS team solved the packaging issue by fitting the cylinder heads from the regular 3800 Buick V6. Moreover, they used different pistons to go with the heads and a standard Garrett turbo instead of the ceramic ball-bearing version of the GNX and a slightly modified intercooler.
On the flip side, the heads provided better airflow, and the ECU chip that limited the GNX mill to 124 mph (200 mph) was swapped with an upgraded one, allowing the more aerodynamic and better-handling Trans Am to go over the 150 mph (241 kph) mark.
The result of the modifications didn't have a negative impact on performance. However, marketing a car that was more powerful than GM's flagship Corvette would have resulted in some internal quarrels, so Pontiac avoided that by rating the 20th Anniversary's turbocharged V6 at 245 hp - exactly the same figure as the 1989 Corvette and 31 ponies less than the 1987 GNX.
The quickest American production car of 1989
Photo: Mecum
Despite the factory output rating, which was about 50 hp farther from the truth, the 20th Anniversary Trans Am could embarrass the 1989 Corvette in a straight line all day, every day.
Among others, Car and Driver magazine published its road test results in its June 1989 issue, highlighting the limited-edition Pontiac's jaw-dropping performance.
According to the magazine, it accelerated to 60 mph (97 kph) from a standstill in 4.6 seconds and ran the quarter mile in 13.4 seconds at 101 mph (162 kph).
The article concluded that the 20th Anniversary was "the quickest 0-to-60 sprinter available in any U.S. production-car showroom—at any price."
Going head to head with the GNX
Photo: Mecum
With the reviews pouring in, enthusiasts started debating whether or not the 20th Anniversary could beat the GNX in an old-fashioned quarter-mile race.
Among them were the folks at Muscle Car Review magazine, who decided to settle the debate by organizing a race between the two turbocharged muscle cars.
The results were published in the magazine's July 1989 issue. The head-to-head contest consisted of two quarter-mile runs, with the first being won by the GNX, which passed the traps in 13.34 seconds at 104.11 mph (167.54 kph), as opposed to the Trans Am's 13.64 seconds at 102.72 mph (165.31 kph).
The Pontiac won the second run with a 13.60-second run at 101.18 mph (162.83 kph), but since the Buick passed the traps just one-hundredth of a second later (13.61), it took the overall win.
While the test didn't necessarily settle the issue, it proved that neither of the 1980s legends was considerably better.
The not-so-stock Pace Car
Photo: Mecum
On May 28, 1989, the turbocharged Trans Am made its highly anticipated Indy 500 pace car debut. As Pontiac stated, the actual pace car was no more than a stock 20th Anniversary that only received decals and a light bar—except it was not.
Like the limited-production version available to the public, the pace car was equipped with the same suspension system, the same large front brake discs hugged by two-piston calipers, and the 3.8-liter turbocharged Buick V6. However, the engine received a more efficient intercooler and a different ECU chip.
Nevertheless, compared to past pace cars, which were heavily modified production versions, the 20th Anniversary Trans Am used for the 73rd edition of the legendary race was a lot closer to stock specification.
The 20th Anniversary Trans Am today
Photo: Mecum
The turbocharged special was, as you can imagine, a marketing hit of epic proportions. People rushed to Pontiac dealerships to order one, and even though some dealers raised the prices exponentially, they still couldn't prevent eager enthusiasts from flooding their establishments.
Because of this, Pontiac decided to slightly increase production up to 1,555 units, excluding the prototypes and the cars used at the Indy race.
Still, if the division had doubled the initial figure, its dealers would've probably sold every example without breaking a sweat.
Despite its popularity back in 1989, today, the 20th Anniversary Trans Am has been forgotten by a surprising number of enthusiasts, as evidenced by its value on the classic car market.
Unlike the GNX, which fetches six figures nearly every time it goes under the hammer, a low-mileage 20th Anniversary Trans Am in great shape can be brought for less than $50,000.
Even if some have forgotten that it ever existed, the 1989 Pontiac 20th Anniversary Trans Am remains one of the greatest muscle cars ever produced.
For more information and a virtual tour of this turbocharged legend, we recommend watching the YouTube video below by Muscle Car Campy.
Vlad's first car was custom coach built: an exotic he made out of wood, cardboard and a borrowed steering wheel at the age of five. Combining his previous experience in writing and car dealership years, his articles focus in depth on special cars of past and present times. Full profile
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