10 of the Rarest and Most Powerful Classic Muscle Car Convertibles

2. 1966 Shelby GT 350 Convertible

Most muscle car enthusiasts will say the first model year for the Shelby Mustang convertible was 1968, but this is only partially true. In 1968, Shelby offered convertible versions for sale to the public as a regular production option, but Carroll built the first convertibles himself in 1966 as a secret project.

They introduced the Shelby GT 350 in 1965 as a race-ready version of the Ford Mustang. It soon proved itself on the race tracks all over the world. By 1966, the GT350 was a global success and Ford praised Shelby for giving them a race car that could beat both the Chevy Corvette and Europe`s finest sports cars of the era.

In 1966, Ford offered the GT350 with street-friendly equipment, an automatic gearbox and new color choices. This move affected its popularity and helped sell more cars. However, there was still no regular convertible option. But, at the end of the 1966 model year, Carroll Shelby decided to produce a limited and secret run of six GT350 convertibles to give to his family and friends.

This was a sort of commemorative edition to celebrate the success of the GT350, as well as a prototype for the potential production of convertibles. Each car received full options, like air conditioning and a roll bar. They also painted each car in a different color with its signature white racing stripes.

For years, mainstream muscle car enthusiasts were unaware of the 1966 GT350 convertibles simply since the owners kept them in private collections, rarely showing them in public. Today, four are known to exist and two are among the missing.

3. 1970 Dodge Challenger R/T Hemi 426

Even though Plymouth had the Barracuda, the first pony car model they introduced two weeks before the Ford Mustang, its stablemate, Dodge didn’t enter the segment until 1970. Some muscle car historians said Dodge was almost late for the party, but the Challenger was so good, that it truly left its mark and reserved a place in motoring history. Mopar’s E-Body models, the Barracuda and the Challenger were brand new for 1970. They featured new designs, enhanced construction and wider, longer bodies.

There were no significant mechanical differences between the Barracuda and the Challenger, only the design, although they had some interchangeable bodywork parts, as well. They gave the Challenger the full firepower of Mopar’s engines, so buyers could get the powerful 383 V8, the big 440 or the famous 426 Hemi. Since the Challenger was a true muscle car, most models they sold were coupes, even though the convertible was also available.

In 1970, Dodge produced only nine convertible Challengers with the Hemi making this model one of the rarest, as well as the most powerful muscle car convertibles built in those golden years.

4. 1967 Chevrolet Corvette L-88 Convertible

The second-generation Chevrolet Corvette or C2 was available from 1963 to 1967. It was arguably one of the most beautiful and aggressive-looking cars from the muscle car era. It caused a sensation when Chevy introduced it because it was modern looking, even when the third generation Corvette replaced it in 1968. The Corvette C2 introduced many important things to the Corvette lineup, such as big block power, independent rear suspension, and disk brakes all around.

It was also a popular and successful racing car in the hands of many private teams. The Corvette aficionados claim the last year for the C2 was also the best because Chevy discretely restyled it. It featured an interesting hood scoop and new engine choices. Although they introduced the big block 427 Corvette in 1966, it was further refined with four levels of power for the 1967 model year.

The list started with a 390 HP, 427 V8 and ended with an extremely rare, valuable and powerful L-88, 427 V8. Corvettes equipped with this engine were in a class by themselves since the aluminum head L-88 produced close to 600 HP. It also came with a mandatory heavy-duty suspension, brakes and handling package.

Chevy developed this option for racers and it was expensive, almost doubling the price of the basic 1967 Corvette. This made it one of the rarest cars ever, with Chevy building just 17 as a coupe and only three as a convertible. It goes without saying that the L-88 powered 1967 Corvette convertible is extremely expensive and rarely comes up for sale.

5. 1970 Plymouth Roadrunner Hemi Convertible

When it first appeared in 1968, the Plymouth Roadrunner proved to be an influential and important muscle car. Not only did it introduce a new trend of wallet-friendly, yet fun cars, it was also a strong seller that affected the entire market. The whole idea behind the Roadrunner was simple: present an inexpensive yet powerful model and add a crazy name and graphics to attract people on a limited budget mixed with a strong need for performance.

The Roadrunner had a bench seat and manual steering and didn’t have any luxury options, but it came with a powerful 383 V8 as the base engine. Buyers could also opt for a 440 or the mythical Hemi 426. In 1969, Roadrunner got a convertible option for those buyers who wanted an open-air driving feel, but most Roadrunners were two-door hard tops. In 1970, Roadrunner got a mild restyling with a new front and rear end, but the convertible option remained. For just above $3,000, you could be the proud owner of an open-top Roadrunner in 1970.

However, if you wanted a few options and a Hemi engine, the price would quickly rise to over $4,000. This was one of the main reasons Plymouth built only four Roadrunner Hemi convertibles in 1970, making it one of the rarest muscle cars and a valuable part of Mopar muscle history.

6. 1970 Buick Grand Sport 455 Convertible

The Buick GS 455 is a special and interesting car in muscle car mythology. As most people know, Buick was a luxury car brand and as such wasn`t interested in the muscle car hype of the mid-’60s. However, despite its restrained image and older clientele, Buick produced a couple of memorable machines with high horsepower ratings and unmistakable style. Cars like the Riviera GS, Wildcat, and Skylark GS were true muscle cars that offered uncompromised performance, as well as a high level of luxury and quality.

But, in 1970 when GM lifted its ban on engine displacement, Buick decided to introduce one strong model they named the Grand Sport 455. This car featured the famous 455 V8 rated at 360 HP, which could launch the big, heavy car to 60 mph in just around 6.5 seconds. This was lightning fast in 1970 and its speed is still respectable today. Since it was a Buick, they equipped the GS 455 with updated standard equipment and it had a long list of optional extras.

Every GS 455 came with heavy-duty suspension, beefed-up steering and brakes, and much more. The price was close to $4,000, which was a hefty sum for the day, but the GS 455 coupe proved popular with over 8,000 built. However, they offered GS 455 as a convertible as well, and just over 1,000 were built.

In comparison to some other models on our list, 1,000 cars may seem like a fairly big number. However, those GS 455 convertibles are rare due to the fact that the market forgot about them, making them treasured finds.

7. 1961 Chevrolet Impala SS 409

The legendary SS or Super Sport package has its place in muscle car history as an important model that promoted performance to the public. This was one of the first high-performance automobiles that were relatively affordable and fast. Everything started when Chevrolet decided to transform its 409 truck engine to use for passenger cars. They found out that the unit was extremely powerful and it could outrun all other cars on the road.

Just by making some mild modifications to the engine, it could produce up to 409 HP, which was enough to propel the Impala from a standstill to 60 mph in six seconds flat. At that time, that was Corvette territory. So, as a mid-year introduction, Chevrolet presented the SS package, which featured bucket seats, a sports trim and other special details. It came with the 348 V8 engine with 350 HP under the hood, too. However, the most interesting option was the 409 V8 with up to 409 HP, if you optioned for a dual quad intake system.

Chevrolet sold over a million of its full-size models in 1961, but they only made 456 Impalas S. Out of those 456, only 142 Impalas came with the 409 engine. The exact number of Impala SS 409 Convertibles is unknown, but Chevrolet historians speculate they made around 45 of this cool-looking and immensely powerful open-top cruisers.

Interestingly, the 409 option was available for all Chevrolet full-size models in 1961, so it was possible to install this engine in plain-looking sedans and wagons, but those cars have yet to surface. As you may expect, the 1961 Impala SS 409 is one of the most valuable cars in Chevrolet’s muscle car history.

8. 1970 Chevrolet Chevelle SS 454 LS-6 Convertible

The Chevrolet Chevelle was always a popular muscle car, combining an affordable price, contemporary design, and powerful engine. In the 1960s, customers could order the Chevelle with a 396 big block V8 engine. It was the biggest, most powerful unit rated at 325 or 375 HP, which was more than enough to be a significant player in the muscle car segment.

But, in 1970, GM’s ban on displacement for intermediate models was lifted, which meant that the Chevelle could get the biggest and the most powerful engine GM had to offer. With the new design, improved mechanics, and one new big block unit, the Chevelle was set to conquer the drag strips in 1970. The mighty new option was the legendary 454 V8 engine. In standard trim, it was rated at 360 HP, which was much lower than the real number. However, there was an even more powerful version called LS-6. The LS-6 had borderline racing compression of 11.25:1. It used a bigger carburetor and had much stronger engine internals. It was rated at 450 HP; however, it could produce around 500 HP.

Even though the SS option was quite popular in 1970, only around 3,700 cars received the mighty 454 V8 engine. The LS-6 equipped cars were even rarer and Chevy only produced 20 convertibles, making this Chevelle one of the rarest muscle car ragtops in the world.

9. 1969 Ford Mustang 428 CJ/SCJ Convertible

Ford`s best-selling pony car, the Mustang, got its third restyling for 1969 and grew in size. The new body was bigger and wider, but the wheelbase stayed the same. All three body styles were present so buyers could choose between the elegant convertible, standard coupe and sporty-looking Sportsroof fastback. But the competition was tougher than ever and Mustang sales showed Ford that it needed to invest in Mustang to maintain its popularity.

The biggest news for 1969 was the famous Cobra Jet 428 V8 engine, which was available in two versions, the Cobra Jet and Super Cobra Jet (SJC). The difference was in several high-performance parts in the SJC. Interestingly, Ford rated this engine to a conservative 335 HP, but in reality, the output was closer to 450 HP. Mustangs equipped with this engine could see 60 mph in as little as 5.5 seconds.

The Cobra Jet 428 was available in all three body styles and with the GT package. As expected, they installed most in the coupes of the Sportsroofs, but 122 people ordered the mighty Cobra Jets and Super Cobra Jets in the convertible body style.

Out of that number, the rarest is the Q-code Super Cobra Jet without the GT package and with a manual transmission. They only build five of these cool-looking, top-performing machines.

10. 1965 Pontiac Catalina 2+2 Convertible

In the mid-1960s, the Pontiac GTO was the car to have since it was on the forefront of the exciting new muscle car movement. With its performance, powerful engine and great Pontiac styling, the GTO was the perfect car for the moment. But, it wasn`t the only stellar performance machine coming from Pontiac, and in 1965, there was another pure muscle car icon in the form of the Catalina 2+2.

Behind this strange name hides a full-size Catalina model, available as a coupe or a convertible, but with a performance twist. The regular Catalina was a handsome, decent-selling model, but in 2+2 form, it transformed into a true Gran Turismo with a luxury interior and fire-breathing engine. Since the Catalina was a full-size model, it was eligible for engines over 400 CID, according to GM rules of the time.

The Catalina 2+2 came with the famous 421 V8, and drivers could get the Tri-Power intake system. This power intake system was the same as on the GTO, and it could boost the car’s power to 376 HP. Car buyers could also order limited-slip differentials, heavy-duty steering, brakes and a whole lot more, making the Catalina 2+2 well-appointed but unfortunately, expensive, too.

The top-of-the-line 2+2 cost over $4,000 which was a hefty sum and much more than the similarly equipped GTO, for example. Pontiac produced around 11,000 of these fine machines in 1965, but only made around 200 convertibles, making the Catalina 2+2 rag top a rare find, indeed.