The world of muscle cars is a rich and varied one. This automotive category has a history that stretches back over half a century, and has played an essential role in American car culture. There is a muscle car out there for all kinds of drivers and personal tastes; some, however, are harder to find than others.Whether it’s a unique powertrain combination, a package that few customers chose to buy, or a limited-edition version built for a special occasion, there are muscle cars out there that the average car enthusiast is unlikely to spot on the road in a lifetime. In this list, we have collected some of the rarest models in the muscle car world.Items are listed in chronological order, from the oldest to the newest. 1963 Chevrolet Impala Z11 1963 Chevrolet Impala Z11 Mecum 1The third generation of the Chevrolet Impala was also the first one to get a high-performance variant in its lineup. The Regular Production Option (RPO) Z11 variant was based on the Sport Coupe version of the model, a two-door hardtop. The Impala Z11 was created with weekend track drivers in mind: a car capable of handling daily-driver duties and offering extra performance when called for.The Impala Z11 was given a host of mechanical upgrades, such as a two-piece aluminum intake manifold, a revised compression ratio, and a cowl-induction air intake system. The bodywork was made from aluminum, and several elements such as the radio and heater were removed in order to save weight. 1966 Ford Fairlane 500 R-Code 1966-ford-fairlane-500-r-code-mecum-1Although the Ford Fairlane did not start out its life as a muscle car when it was released in 1955, as time went on its character became more performance-oriented. In 1964, Ford had already released a sportier version of the model, oriented towards drag racing: the Fairlane Thunderbolt, of which just 100 units were built.Two years later, however, Ford decided to create an even rarer high-performance Fairlane, which wasn’t quite as drag strip-ready as the Thunderbolt but could still hold its own. This version was called the Fairlane 500 R-Code, and it was equipped with the 427 cu. in. (7.0-liter) Cobra V8 engine. 1966 Oldsmobile 442 W30 1966-oldsmobile-442-w30-mecum-1The Oldsmobile 442 was first introduced in 1964, but it wasn’t until two years later that the rare W30 package was introduced to the lineup. This package offered upgrades such as forced air induction (through ducting that ran from the high-beam headlight openings to the under-hood air cleaner), revised valve springs, and revised camshaft tuning. The 442 W30 was built to compete in NHRA stock car racing; as weight saving was paramount, the package also included a stripped-down interior.All units were equipped with a 6.6-liter (400 cu. in.) V8 engine, paired with a four-speed manual transmission. Just 54 units were built in 1966, making this version of the 442 one of the rarest Oldsmobiles ever built. 1967 Ford Mustang Shelby GT500 Super Snake Ford Mustang Shelby GT500 David Newhardt Mecum (1)The Super Snake Mustang was, up until 2018, the rarest car on this list as only a single example existed. It was created by Carroll Shelby, who installed the 7.0-liter V8 engine from the Le Mans-winning GT40 in a GT500 Mustang. He also added a set of rare Goodyear Thunderbolt tires. This model, however, never made it to the production stage.In 2018 a set of 10 continuation cars were built to give the Super Snake the production run it deserved. They were made by converting 1967 Mustangs, with custom engines being installed and a set of cosmetic details being added to recreate the Super Snake as faithfully as possible. 1969 Dodge Charger Daytona 1969 Dodge Charger DaytonaThe iconic Dodge Charger arrived on the market in 1966; three years later, a version of the model that has become just as famous made its debut. This version of the model was made for NASCAR homologation purposes, hence the Daytona name. As a result, it had a very small production run, with just 503 units built over a single year.A choice of two engines was available: a 7.2-liter V8 was standard, but a 7.0-liter Hemi V8 (which produced 425 hp) was available as an option. Just 70 customers chose to have this engine installed in their Daytona. A four-speed manual transmission and three-speed automatic were available to choose from. The Daytona name was brought back multiple times over the following decades, and is currently used for the electric version of the Charger. 1970 Plymouth Barracuda Hemi Convertible 1970 Plymouth Hemi Cuda convertible frontThe Barracuda is possibly the most famous model ever produced by Plymouth, and one that has cemented the brand’s place in automotive history. An icon of the muscle car world, it was in production for a decade. This particular version, however, was far rarer. The Hemi ‘Cuda Convertible combined the 7.0-liter Hemi V8 engine with the convertible body style, and it was only around for two model years, with fewer than 30 units produced.Since there were so few of these cars around to begin with, the ones that have survived to the present day in good condition come with an eye-watering price tag: examples of the Hemi ‘Cuda Convertible can fetch over $2 million. 1970 Chevrolet Chevelle 454 SS LS6 1970-chevrolet-chevelle-454-ss-ls6-mecum-1This range-topping variant of the Chevelle was equipped with the RPO Z15 performance package, which added the 450-hp, 7.4-liter (454 cu. in.) V8 engine, as well as new carburetors and other mechanical upgrades. It's reported that 4,475 examples were built, but information on how many of each body style were sold is not so clear; it's estimated that between just 20 and 80 convertibles were produced.Regardless, very few examples have survived to the present day, so anyone who has one in their garage is part of a very exclusive club: today, a Chevelle 454 SS LS6 can have a price tag above the six-figure mark. 1971 Pontiac GTO Judge Convertible 1971-pontiac-gto-judge-convertible-mecum-1The “Judge” was a version of the Pontiac GTO known for its quirky character. Named after a comedy routine and marketed with a lighthearted advertising campaign, it was equipped with a package that included wider tires, a Hurst shifter, and a rear spoiler. Custom decals distinguished it visually from the regular GTO.Although 11,004 examples of the Judge were built in total between 1969 and 1971, just 17 units were built in convertible form in 1971, when the Judge package was canceled mid-year due to rising costs. Of these 1971 convertibles, most were fitted with the 6.6-liter V8, but three combined a 7.5-liter V8 engine with a four-speed manual transmission, making them an even scarcer find. 1981 Stage II Turbo Z Yenko Chevrolet Camaro 1981 Yenko Turbo Z Chevrolet Camaro Stage II(6)This version of the Camaro is one of the rarest ever produced. Racing driver and car dealer Don Yenko was responsible for its creation. Yenko had a long history of customizing Camaros, building unique high-performance creations: the first run of “Yenko Camaros” arrived in 1967, with a total of just 57 cars.14 years later, however, Yenko was dissatisfied with the direction the Camaro had gone in after the oil crisis. He decided to build another custom car bearing his name, using his modification skills to squeeze additional performance out of a tame Malaise Era Camaro. The result is an impossible-to-find car, which has become legend in the muscle car world. 1987 Buick GNX 1987 Buick GNX front 3/4The last and most recent car on our list is the Buick GNX created as a kind of farewell edition for the Regal’s second generation which was coming to an end. Its name stood for “Grand National Experimental”, as the GNX was a limited-edition version of the second-gen Regal’s Grand National spec.The GNX was the product of international collaboration: it was designed with the help of the McLaren racing team, which added several mechanical modifications to boost its performance (such as a Garrett turbocharger and upgraded intercooler and exhaust). Buick, meanwhile, contributed with a sportier interior and exterior styling package, which gave the GNX a more aggressive look.Sources: Buick, Ford, Chevrolet, Pontiac, Plymouth, Dodge, Oldsmobile