Ever since the term was coined to describe the 1964 Pontiac GTO, muscle cars have always been about bringing V8 thrills to the average buyer in a relatively affordable package. In the ‘60s and ‘70s, the segment thrived on big block performance and street-racing credentials, but these cars were never supposed to be super-expensive. They were sports cars for the everyman – faster and more aggressive than other cars on the roads, but not necessarily out of reach for the average Joe.Today, however, muscle cars that happened to be produced in low numbers easily outprice brand-new exotic supercars designed to siphon money from the rich. And while you can still find several badass big-block V8 muscle cars selling for relative bargains in great condition, the ridiculously rare ones we’ll talk about in this article make new supercars look affordable by comparison. 1970-'71 Plymouth Hemi Cuda Production: 652 Units (Coupe); 25 Units (Convertible) Via: Mecum AuctionsBuilt on the E-body platform shared with the Dodge Challenger, the third-generation Plymouth Barracuda is a desirable classic muscle car that collectors will pay a pretty penny to own. Find one with the rare NASCAR-spec Hemi 426 V8 under the hood, though, and you’re looking at an average used price of $345,000 according to Classic.com. Just 652 of these found their owners, each factory rated at 425 hp and 490 lb-ft, putting them among the most capable muscle cars of their time.However, the distinction of the rarest and most expensive Cuda belongs to the ridiculously rare convertible variants. Only 25 have ever been built (Hemmings): 14 leaving the factory in 1970 and just 11 in 1971. With values climbing well into seven figures, these brochure-worthy classic muscle cars will make most modern supercars look affordable. Want to really take things to the extreme? Look for one with a factory 4-speed manual transmission – a box that only three 1971 Hemi Cuda buyers ticked.Via: Mecum Auctions If you’re wondering why so few were built, keep in mind that the golden age of muscle cars was already nearing its end when the Hemi Cuda arrived. It’s not like these were rare by design, though – simply not many people ever opted for them. Not only was the Hemi V8 an expensive $883 option on top of the Cuda’s $3,291 MSRP (Hemmings), but it also pulled with it sky-high insurance premiums due to rising gas prices and emissions regulations.Since there’s no obvious reason to market this car other than to stand out and look unique, the car community is lucky Plymouth decided to offer something as badass as a Convertible Cuda at all. Here’s one that went under the hammer only recently in 2024 at Mecum for a mind-numbing $2.3 million. That’s roughly the price of the world’s fastest electric hypercar – the new Rimac Nevera R. 1969 Chevrolet Camaro ZL1 Production: 69 Units Mecum The Camaro ZL1 owes its existence to an Illinois Chevy dealer named Fred Gibb, who used a Loophole in Chevrolet’s ordering system to bring Camaros with the all-aluminum Can-Am-derived 427 big blocks to the streets. The models were codenamed ‘COPO 9560, and each was rated at 430 hp and 460 lb-ft, which made them the most powerful street-legal muscle car in the 60s. In the end, 69 units ended up reaching buyers according to Hagerty: 22 equipped with automatics and 47 with four-speed manual transmissions.Mecum Today, based on five recent sales, Classic.com puts the average value of a 1969 Camaro ZL1 at a whopping $589,900, putting it well into brand-new supercar territory. However, well-kept models will reach close to seven figures, such as this black example that fetched $825,000 at a 2021 Mecum Auction.That kind of money is quite hard to spend on just one supercar without stepping into hypercar territory. However, if you were to spend it all, you could easily buy a fully optioned 1000-hp Lamborghini Revuelto with a naturally aspirated 6.5-liter V12 paired with 3 electric motors. Ford Mustang Boss 429 Production: 1359 Units Bring a Trailer The Boss 429 marks the pinnacle of the golden age of muscle cars for Ford. Its purpose? Simply to homologate the ridiculously powerful 429 Boss “Semi-Hemi” V8 for NASCAR – a task that required 500 street-legal Boss 429 Mustangs to reach buyers. It wasn’t as simple as shoving this big block in a Mustang, either; Ford had to go to Michigan-based builder Kar-Kraft to modify the first-gen Mustang’s engine bay to fit the monster V8 inside – a feat they achieved by widening the shock towers, relocating the front suspension components, and shoving the Mustang’s battery in its trunk.The result was one of the fastest and most capable muscle cars of its age, unleashed to fight against Hemi 426-powered Mopars and big-block Camaros and Corvettes. Ford notoriously underrated the car at 375 hp, but they weren't fooling anyone. Modern dynos put the actual power output of restored 429s at 510-520 hp.Bring A Trailer The Boss 429 is not the rarest muscle car that Ford ever put out, with models like the Fairlane Thunderbolt and Torino King Cobra being technically rarer, but it’s easily among the most famous and valuable. Only 1359 units have ever been produced: 859 in 1969 and another 500 in 1970 (Hagerty).Today, a Boss 429 has an average auction price of $329,974 on Classic.com, but pristine examples like this gorgeous orange one that sold on Mecum easily fetch north of 500 grand. That’s roughly the same value as a brand-new Ferrari SF90 – until recently, the brand’s flagship supercar featuring a 986-hp hybrid twin-turbo V8 sending power to the rear wheels. But I imagine that it will still turn fewer heads than the Boss 429. 1967 Chevrolet Corvette L88 Production: 20 units Via: Mecum Auctions You may call it a sports car, but when it comes to combining ridiculous rarity with exorbitant values, the Corvette L88 is still king. You may think the L88 Corvette deserves more attention now, but back in the day, only a handful of enthusiasts were even aware of its existence. Chevy didn’t even bother advertising it, so it mostly slipped under the radar in the ‘60s.See, the brand didn’t want regular buyers anywhere near this car, partly because of the massive insurance premiums associated with selling a 500+ hp car, and partly because these were really just race cars with licence plates with very little in terms of creature comforts. So, Chevy slapped a comically low 430-hp rating to make the L88 seem less powerful than the L71, and consequently, only pro drivers who knew what they were getting ever opted for the $1.023 L88 engine in their Vette. In the real world, however, the L88 put out mind-bending power outputs – as high as 560 hp. This gives it a solid claim to the title of the most powerful muscle car of the ‘60s (if you know one that's more powerful, we're all ears).Via: Mecum Auctions Still, only 20 buyers opted to have an L88 under the hood of their Vettes in 1967, making the C2 the rarest Corvette ever offered with an L88. However, 80 more got the engine for their C3 Vettes in 1968, and 116 in 1969 – putting the total number of Corvette L88s at just 216.Now for the juicy bit. Because of all of this, the L88 remains the most valuable Corvette anyone could buy. Five recent sales put the car’s average value at a ridiculously steep $2.4 million on Classic.com, while a red 1967 example that fetched $3.85 million remains the most expensive Corvette ever sold.Interestingly, there are rarer Corvettes out there, such as the 16-example L89 C2. And while these were specced with the less capable L71 427/435 HP big-block engines and lightweight RPO L89 aluminum cylinder heads, they too have been known to fetch well over seven figures at auction. 1965 Shelby GT350 Production: 525 Units Bring A Trailer The GT350 was Shelby’s more hardcore and rebellious take on the first-generation Mustang. Fitted with a 306-hp 289 HiPo V8 under the hood, it was designed to race in SCCA’s B-Production class and shed weight and features left and right, including the rear seats which were replaced with a fiberglass shelf. It ended up taking the win at its first race season, solidifying its status as a motorsports-tested street machine.Only 562 were built and this includes the rare GT350R produced in only 36 examples, designed only to be driven on the track. Both the GT350 and the GT350R are legends now, and they’re up there with the most valuable garage queen muscle cars in the world. While the regular GT350s already fetch a ridiculously steep $321,282 (Classic.com), the coveted R versions are worth millions. 1970 Dodge Challenger R/T Hemi Production: 365 Units (Coupe); 9 Units (Convertible) Mecum One of the most capable engines offered in road-legal muscle cars at the time, it makes sense the Hemi V8 wouldn’t just be a one-time thing on this list. However, despite being built on the same platform, the Challenger R/T Hemi Convertible is even rarer than its Plymouth sibling. Sure, most of its value comes from its rarity and the legendary V8 under its hood.But while every Hemi V8 muscle car is ridiculously quick and underrated from the factory, R/T Challengers with these under the hood easily clocked 13.1-second ¼-mile runs in the ‘70s, making them the quickest muscle cars of the decade. The Fastest Quarter Mile Time For A Big Block Muscle Car In The '70sCoupe models are easier to find with 365 leaving the factory in 1970, but if you’re looking for the rarest, it’s the Convertible version you want. Only nine ridiculously desirable examples ever managed to reach buyers, each worth north of a million bucks according to the most recent auction information available. Here’s a gorgeous green one that traded hands in 2016 for a hefty $1.65 million – more than enough for any supercar and even some hypercars. Several Other Convertible Muscle Cars Are Now Worth A Fortune Too You've definitely noticed the pattern by now: low-production convertible versions of popular muscle cars commanding ridiculous sums. That all makes sense, but some of these muscle cars are so rare, I'd be remiss not to mention at least a few more in this article. 1967 Dodge Hemi Coronet R/T Convertible Mecum Auctions The Coronet is a cool muscle car in its own right, but some gearheads may not know that Dodge offered a Hemi under their hoods, and only 628 Coronets ever got it. The same one you'd find in the Hemi Cuda or the Charger and Challenger R/T. However, only three buyers ever got their hands on a Hemi-powered Coronet with a drop-top, making this arguably the rarest Mopar the rarest muscle car ever produced. 1970 Chevrolet Chevelle SS 454 LS6 Convertible Mecum Auctions The Chevy Chevelle SS LS6 tops many gearheads' lists as the most badass muscle car of the ‘70s, and for good reason. The LS6 454 big block V8 under its hood made it the most powerful factory-rated muscle car of the decade, and its performance on the streets backed it up. However, it’s not exactly a hidden gem, since 4,475 found buyers. The same can’t be said about the Convertible version, though. Fewer than 200 of these muscle cars are known to exist. 1971 Pontiac GTO Judge Convertible Via: Mecum Auctions Marketed toward younger audiences and famously painted in bright “Carousel Red,” the GTO Judge became an instant hit when it debuted on the market in 1969. And while these are highly sought-after muscle cars today, offering the venerable Ram Air III and IV V8s, the convertible version of the 1971 GTO Judge is by far the rarest. Only 17 units are known to exist, and in 2016, a red one sold for $192,500 in Arizona.