American Muscle. No other two words can elicit the emotions and memories of the old days better. Many auto enthusiasts got their start in the dirty home garages of their parents and older siblings, tooling and tuning cars that were loud, fast, and unapologetic.

While many of the cars attained iconic status in the world of gearheads everywhere, some were forgotten and some were simply not very good.

But there are some cars in a completely different class. Not only for the beauty outside and under the hood, but also for the rarity. These six hot rods are a collectors dream. When and if these cars do show up on the open market, the works of art can sell for upwards of a cool million.

Keep your eyes peeled at your next auto show for these seldom seen beasts. Each one could be the most expensive car in the show. 

1970-71 Plymouth Hemi Cuda Convertible

Technically a cheat, as this is a two for one, but both are extremely rare.

Only five of these four-speed Plymouth Cuda Convertibles were built in 1970. The following year, there were only two. One of those two sold for an unheard of $3.5 million at auction.

The reason the 1971 Hemi is so rare is it was the last year the e-body was used to accommodate the 426 Hemi before it simply got too expensive to produce or insure. Plus, if you were lucky enough to get the super track pack, the car was trimmed out for the dragstrip.

Of course, these early 1970s Cudas in all the varieties are extremely rare, but the convertibles are genuine four-leaf clovers, despite some questionable build quality and handling issues.

1970 Chevy Chevelle SS 454 LS6

For sure, it is not the fastest or most equipped Chevrolet, but it is definitely one of the rarest. And for its time, it was indeed among the fastest cars on the road.

The Chevelle SS boasted a Big Block 454 with a Holley four-barrel backed by a Turbo 400 transmission that would put a smile on the face of any gearhead.

1971 Pontiac GTO Judge Convertible

The Judge version of the GTO was canceled early on, making this one a rarity almost immediately. Only 357 hardtops and a scant 17 GTO convertibles were built in 1971. It came with a very appealing 455 High-Output V8 engine under the hood.

1969 Chevy Corvette ZL-1

An extension of the L88 line, the ZL-1 offered the option of an all-aluminum 427 in place of its cast-iron twin. While there are officially only two recognized as being built, there could have been more. But whatever the actual number, the ZL-1 is definitely one of the rarest Corvettes available.

1967 Dodge Coronet R/T 426 Hemi

If you are in the market for a 1967 Dodge Coronet R/T edition, just be aware: there were only two made. One was a four-speed, one was an automatic. The extra expense of the 426 Max Wedge option in 1967 led to only two orders being made.

Bonus: 1957 Chevy Bel Air “Project X”

There is only one “Project X”. Dubbed by Hot Rod Magazine as the “Greatest Hot Rod of All Time”, the iconic yellow Bel Air is one of the most famous Chevys.

Appearing in the film The Hollywood Knights, with actor Tony Danza behind the wheel, the gorgeous Chevy gets into a grudge match with a fast-sounding AC Cobra.

It has been a project car for over 50 years and every now and then goes on the car show tour, so be sure to see when you can. It truly is a one-of-a-kind hot rod.