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What Is The Rarest Muscle Car Ever Made?
Many classic muscle cars could have made the list, so we sympathize if we left off your favorite. Many of the picks were convertible versions of larger production models, but in other cases, they were concept cars or modified versions with race car roots. Regardless of our parameters, here are our votes for the rarest muscle cars.
1963 Chevrolet Impala Z-11
While many classic car enthusiasts point to the 1964 GTO, the reality is that car companies were experimenting with large block engines in mid/full-sized cars long before the GTO hit the streets. The 1963 Z11 Impala sported a souped-up 427 V8, giving it a ridiculous 13.1:1 compression ratio. The reported power rating was 430 hp and 575 lb-ft of torque.
Any Chevy owner who wanted to beat Ford on the strip needed to RPO this particular engine option, even though it wasn’t cheap, costing over $1240 more than the MSRP of $2,774. With the addition of the Z11 option, the Impala could reach over four grand, a ton of money back in the early sixties.
Only 57 Z11 Impalas were built, and estimates indicate that less than seven or eight exist today. According to Hagerty, the value of these rare Impalas is around $280,000. In good condition, these Impalas are highly sought-after high-performance machines.
1970-71 Plymouth Hemi ‘Cuda Convertible
The ‘Cuda convertible is one of the most iconic muscle cars. One option for the 1971 ‘Cuda was a 426 Street Hemi engine with a power convertible top and a manual transmission. While 348 convertibles were made for the ‘71 MY, only 13 came equipped with the Hemi, and only 3 had the manual transmission. (The ‘Cuda Hemi convertible was rare, with 20 vehicles made in the 70 - 71 production years).
As a mass-produced Plymouth, the convertible version wasn’t cheap costing customers nearly $4,000. It's a shame it didn’t sell more because the car had severe muscle. With the 426 Hemi engine, the ‘Cuda could move down the track in 5.4 seconds for 0 - 60 mph, making it the company of cars like the Road Runner, Dodge Charger, and Ford Mustang Boss 351.
The ‘Cuda convertibles were well equipped with wood-grained instrument panels and steering wheels, AM/FM cassette, and black vinyl high-back bucket seats. The Hemi Cuda set a tone for every muscle car enthusiast for years with dual exhaust, a shaker hood scoop, and comprehensive road wheels.
These convertibles are very rare. A ‘Cuda convertible sold for 3.5 million dollars in 2014. In 2021, a convertible that had been shipped to a French owner received a $4.8 million bid, but the bid was not high enough to secure the deal.
1969 Pontiac Firebird Convertible
Long before its debut as the car from Smokey and the Bandit, Pontiac had been producing the Firebird for a decade or more. In its first generation, the Firebird was a cousin to the Chevy Camaro, sharing the F-platform. Although its lines were smoother and less pronounced than the Camaro, the car sold 189k units in the first two model years it was available.
In 1969, Pontiac offered the Trans Am as a specialty line with an upgraded rear end, suspension, and a finely tuned handling package. The “Trans Am Performance and Appearance Package made its way to 689 Coupes, but only eight convertibles were manufactured for 1969.
The 400 ci Ram III engine (L74) was standard, with the Ram IV induction system as an option. The motor’s power output was listed at 335 hp (although many think that Pontiac followed the usual practice of underreporting). The Firebird offered better than decent track numbers at 5.1 seconds for the 0 - 60 mph. The top speed was 153 mph, which put it squarely into the classic muscle car category.
Each of the eight convertibles was painted Cameo Ivory with Tyrol blue stripes. The interior features included bucket seats with Morokide upholstery. Air conditioning, a wood grain steering wheel, and wooden accents around the instrument panel were options.
Since the ‘67 Firebird Convertibles are rare, they tend to be the car many iconic Pontiac owners flock after. Chances are you won’t be able to find one floating around, but if you do, plan on spending a million dollars or more for the pleasure of owning one.
1971 Pontiac GTO Judge Convertible
When the GTO received a facelift for the 1971 model year, most people felt the muscle car had lost its way due to a GM edict that forced its companies to ratchet down compression ratios. (As motors were prepped for no-lead gasoline. The result was a 455 HO V8 with a measly 335 hp and 8.4:1 compression. The RPO (Regular Production Order) car was made 357 times, with 17 of them being convertibles.
The Pontiac brochures acknowledged the lower compression ratios. Still, they indicated that lower axle ratios would multiply the “tractive forces” of the car, making the Judge faster off the start than any car in their history. Coupled with more sizeable hood scoops, forcing colder, denser air into the 4bbl carb, and backing their high-output engine with a Muncie 3-speed transmission, they were all designed to keep the GTO as the ultimate road car.
While the original MSRP was a mere $3,746, buyers weren’t convinced of the GTO dominance. Pontiac incorporated the GTO as a trim level back in the LeMans lineup and stopped taking orders for the Judge in the spring of 1971.
While this muscle car might not have been the fastest GTO ever built, it is likely one of the rarest American muscle cars. A recent auction in 2023 recorded a $1.3 million sale of a GTO Judge convertible, which makes us wish we had one.
1968 Chevy Camaro Z28 Convertible
There is only one 1968 Camaro Z28 Convertible, so it has to be on the list. During the late sixties, the Camaro was a popular muscle car. Owners who wanted more power than the GM rules would allow had to use a COPO (Central Office Production Order) form to specify the kind of car they wanted. Even though GM intended the form to be used by fleet customers, many customers convinced dealers to use them to get specially designed Camaros. For example, in 1969, the COPO 9560 produced 69 Camaros with a 7.0L V8 (427 ci) labeled ZL1 (primarily for drag racing). But the year before, the form was used by one of the executives at Chevy to produce a one-of-a-kind Camaro convertible.
As the story goes, the head of Product Performance, Vince Piggins, used the COPO to build a convertible Camaro Z28 to convince the General manager of Chevrolet, Pete Estes, about the viability of the Z28 for street use. (The Z28 was a high-performance version Chevrolet had developed for the track). The only problem was that Estes only drove convertibles, and the Camaro Z28 was only made as a hardtop. Piggins instructed the factory to build a one-off Camaro Z28 convertible. Estes was so impressed with the car that he kept the COPO convertible as a personal vehicle. To this day, it is the only convertible Z28 made. (While 1967 saw only 602 Chevrolet Camaro Z28s made, the following year, over 7k units made their way through dealers’ showrooms).
Estes drove the car for about a year before GM took it back, stripped it of the racing parts, and resold it to a front-office employee. It bounced around for about twenty years until 1991 when a new owner paid $172,000 for the car (the highest price ever for a muscle car). If GM hadn’t fooled with it, the car's value would likely be close to a million or more.
1967 Shelby Cobra Super Snake
No list would be complete without the high-performance model developed by Carroll Shelby. When the GT500 was added to the Ford Mustang lineup in 1967, Ford put a 7.0L 428 ci V8 into the car. A beast on the track, the car could run 0 - 60 in 6.5 seconds and a 15-second quarter mile. But when Goodyear needed a car to test its tires, Carroll Shelby asked for more power and instructed Shelby American’s chief engineer, Fred Goodell, to take a GT500 and replace the motor with a 427 ci V8 racing engine from a GT40. (The GT40 Mark II had won at Lemans the year before). A Shelby American employee, Don McCain, suggested that the car be made on a limited production run and offered to the public. The project car was labeled the “Super Snake.”
The engine was a beast producing more than 650 hp (since it was a LeMan racing engine). It was made with a cast iron block, aluminum heads, an aluminum water pump, and a lighter mid-rise intake manifold. The bore and stroke were 4.25 x 3.78, slightly less than the Mark II GT40 engine. The car was equipped with a modified Detroit Lock rear end to provide additional traction and a revised front end to provide additional cooling to the engine. The car also had a “bunch of snakes” exhaust system, which made the car growl every time the accelerator revved up. As Don McCain, would remark in an interview years later, “Everything inside the engine was built to run sustained 6,000 rpms - to race at LeMans.”
When Goodyear sponsored the tire event at their Texas test track, the Super Snake was introduced (equipped with Goodyear Thunderbolt tires). The car reached 150 mph consistently during a 500-mile test. (Reporters said that Shelby pushed the car over 170 mph)
Initially, Ford had planned to produce about 50 of the new GT500 Super Snakes for the general public, but the engine cost a fortune to build. Due to the expense, the production plans were scrapped, with only one of these models having been built. The car sold at a Mecum auction for $1.3 million in 2013.
1967/1970 Dodge Coronet R/T Convertible (426 Hemi)
The Coronet is one of Dodge's most successful vehicles, stretching from its first generation in 1949 through 1976 (it was renamed Monaco in ‘77). Even though the car spanned nearly three decades, some production models are rare. For example, in 1967, Chrysler returned to the drag strip (after a year's absence) with a limited number of specially designed W023 Coronets with a (426 ci) Hemi engine. Only 55 of the WO23 Hemi units were made.
That same year, Dodge offered the Coronet R/T, but with a more powerful Magnum V8 (7.0L 440 ci) as standard, but it did offer the “Street” Hemi as a $908 option. Dodge produced over 10k R/T units that year, of which 628 were convertibles, but only three ended up with the smaller Hemi motor. In 1970, the same situation reoccurred, with Dodge only making 14 Coronet models with the 426 Hemi engine, and only 2 were convertibles.
Even though the 426 Hemi wasn’t as powerful as the 440 Magnum, it was no slouch. The Street Hemi produced 425 hp and bolted down the track in 5.3 seconds for 0 - 60 mph. As an American muscle car, it had no problem keeping up with any competitor that might venture alongside it.
While it might not be the rarest muscle car ever made, the ‘67 car is worthy enough to command $219,000 at an auction in Indianapolis in 2019. (Since then, another has been sold in Florida in 2022). A recent auction for a hardtop Coronet R/T sold for even more, $305,000.
1969 Chevrolet Corvette ZL - 1
Chevrolet redesigned their Corvette for its third generation in 1968 and decided to back up their new beast with more powerful V8 engines. The L88 engine had been out for a couple of years, and the company offered it as a high-performance race-spec engine option that you could technically order. In 1969 the company took it even higher with a all-aluminum 7.0L (427 ci) racing engine coded the ZL - 1.
The engine was a perfect match for the sleeker sports car, partly due to its power but also because the Chevrolet Corvette weighed only 3100 lbs. The combination proved blazingly fast on the track with 0 - 60 mph times nearing four seconds and quarter mile times under 12. The horsepower was officially reported to be around 430 hp but was more in the range of 560 hp. (Underreporting power ratios was standard for the day to keep insurance companies and the federal government from interfering).
There were only 3 ZL - 1 Corvettes sold to the public. (The same treatment was given to the Camaro, which sold 69 units). The biggest drawback to the engine was the price. At nearly $4,000, it was as much as the Corvette’s MSRP. Most young Americans didn’t have that money to spend on a sports car and opted for one of the lower V8 engines. Consequently, the ZL - 1 option and the L88 V8 (which you had to order to get the ZL - 1) were discontinued after 1969.
Of the 38,762 Corvettes made in 1969, these three ZL - 1 Corvettes are considered the rarest of the rare muscle. A recent May 2023 auction saw the only convertible sell for a record $3.14 million.
