1970 Dodge Challenger R/T Convertible Hemi engine

The 7 rarest Hemi muscle cars

Total production of these 1966–71 models is a minuscule 29 cars.

Ten thousand, nine hundred and four. A paltry 10,904. According to Allpar.com, that’s how many 426 Hemi-powered street Mopars left Dodge and Plymouth assembly plants from 1966–71. The engine was available in a long list of models and body styles over the years, including favorites like the Plymouth ‘Cuda and Dodge Charger, and all Hemi cars were equipped with a four-speed manual or a three-speed Torqueflite automatic.

Of course, when many of these cars went to the racetrack when new, and others ended up at the dragstrip later in life. Some are still there, tearing it up on Sunday afternoons. But the majority were cruising the boulevards of America looking for big-block Chevys to pick on.

Today, just as when the cars were new, anything with a Hemi is rare, desirable, and expensive. And while 10,904 seems like a relatively small number, the rarest of the rare were built in incredibly miniscule numbers. In fact, the total production of the seven-lowest production Hemi-powered models adds up to only 29 cars.

With the help of the Wellborn Museum in Alexander City, Alabama, and The Automotive Archaeologist’s Ryan Brutt, we did a little digging and found what we believe are the seven rarest 426-powered street Mopars from the original muscle car era.

1970 Dodge Coronet R/T Convertible

Dodge’s Hemi-powered Coronet R/T convertible was a rival of Chevy’s LS6 Chevelle in 1970. However, while Chevy built fewer than 20 LS6 Chevelle convertibles that year, Dodge pumped out only two Coronet R/T drop tops with the optional elephant motor. That’s right, only two, one with a four-speed and one with the Torqueflite automatic. Both cars survive today. The 4-speed car was recently restored on Velocity’s Graveyard Carz TV show, and the automatic was sold by Mecum auction in 2008. (According to one source, a third car was built and sent to Europe, but we haven’t been able to confirm that.)

Why so few were ordered with the optional Hemi is a mystery, but price likely had something to do with it. The 425-horsepower engine was an expensive extra at $718—that’s $4700 today. Dodge also built just 16 with the 440 Six-Pack engine and only 14 Hemi Coronet R/T hardtops. Some speculate that the odd front-end styling, which was new for 1970, kept street rats away as Coronet R/T production was down from 1968 and ’69.

A 1970 Coronet R/T convertible with the 440 Six-Pack engine in #1 (Concours) condition is worth an average of $129,000, and a numbers-matching Hemi-powered Coronet R/T hardtop sold at a Mecum in 2014 for $305,000. So what might the two Hemi convertibles be worth? Likely near $1,000,000. Maybe more.

1966 Dodge Coronet four-door Sedan

1966 Dodge Coronet four-door Sedan front 3/4 don gartlits
Mecum
1966 Dodge Coronet four-door Sedan

Street Hemi production peaked in 1966 with more than 3300 cars built, according to Allpar.com. That year Dodge even built two Hemi-powered Dodge Coronet four-door sedans and both cars survive today, one red and one white. Both were built with the Torqueflite automatic, and both were reportedly special orders for the Federal Bureau of Investigation for towing and field operations.

The red car sold at Barrett-Jackson’s 2007 Scottsdale auction for $660,000, while the white car has spent time in the ownership and museum of drag racing legend “Big Daddy” Don Garlits. Both cars are equipped with the dual-quad Hemi, Sure-Grip 8 3/4 rear end with 3.23 gears, four wheel drum brakes, and a front sway bar. Dodge also installed a station wagon radiator shroud and a heavy-duty battery. Despite the four-door bodystyle, creature comforts were minimal; the cars do not have power steering, power brakes, or power windows, and no Hemi car was ever built with factory air conditioning.

1967 Dodge Coronet R/T Convertible

1967 Dodge Coronet R/T Convertible front 3/4 green
Mecum
1967 Dodge Coronet R/T Convertible

Dodge finally introduced the Coronet R/T (Road and Track) in 1967 to battle Chevy’s popular Chevelle SS models and, of course, the Pontiac GTO, which lit the fuse on the muscle car wars in 1964. A magazine ad said, “R/T: The Newest Hot One From Dodge.”

The R/T package added image with hood scoops and prominent badges, and horsepower with a standard 375-hp 440-cubic-inch V-8. Optional was the street 425-hp, 426-cu-in Hemi for an additional $457. Big bucks in 1966 (equal to about $3500 today).

The Coronet R/T was popular, but it wasn’t exactly a phenomenon with 10,000 sold, including 628 convertibles, according to hotrod.com. Of those, only three drop tops were equipped with the optional Hemi, one with a Torqueflite automatic, and two with four-speed manuals, making them extremely valuable today. Although a Green four-speed car sold for $269,500 at the Barrett-Jackson’s 2006 Scottsdale auction, one in #1 condition is worth $195,000 today.

1970 Plymouth Road Runner Convertible

Unlike the Coronet R/T in 1967, the new for 1968 Plymouth Road Runner was a phenomenon, with Mopar selling nearly 50,000 in the first year and more than 80,000 in 1969. But in 1970, sales plummeted to around 41,000 cars, and the number of buyers taking the optional Hemi dropped significantly, especially in the convertible body style. Only three Hemi Road Runner convertibles were built for 1970, and only one with the desirable four-speed transmission with the new Pistol Grip shifter.

Remember, there were three engines available in the 1970 Road Runner, the standard 335-hp 383, the 440 Six-Pack rated at 390 hp, and the 425-hp Hemi, which was much more expensive than the 440. A 1970 Road Runner convertible with the 440 Six-Pack engine in #1 condition is worth $149,000, while a Hemi-powered car in the same condition is $253,000. Add an additional 10 percent for the four-speed car.

1970 Dodge Super Bee Coupe

1970 Dodge Super Bee Coupe copper front 3/4
Barrett Jackson
1970 Dodge Super Bee Coupe

To rival the Plymouth Road Runner, which had been a huge sales success, Dodge invented the Super Bee as a barebones, cheaper version of the Coronet R/T. The model debuted in 1968 as a two-door sedan and was also offered as a pillarless hardtop in 1969 and ’70. In 1970, engine options were the same as the Road Runner: A standard 383, an optional 440 with three carbs, or the dual-quad 426 Hemi.

Most buyers went for the more attractive hardtop with the 383, but 32 Hemi hardtop Super Bees were sold in the U.S. in 1970. Most two-door coupe buyers (3630 were sold) also went for the standard 335-hp 383, but 196 went for the 440 Six-Pack and only four paid up for the Elephant. The four Hemi cars were all equipped with the desirable four-speed.

A 1970 Hemi Super Bee with a four-speed in #1 condition is worth $122,500.

1966 Dodge Coronet 440 Convertible

In 1966, Mopar was still figuring out the whole muscle car thing. The high-performance 375-hp, 440-cu-in wedge engine was still a year away, and the six-pack version with multiple carburetion and 390 hp wouldn’t debut until late in the 1969 model year. Mopar was behind in the image department as well, with the R/T, Road Runner, GTX, and Super Bee still in the future.

But Mopar did have the Hemi, and a new street version made its debut with 426 cubic inches, two four-barrel carbs, and a 425-hp rating. Walk into a Dodge dealer and you could buy one in a Coronet hardtop, two-door sedan, or convertible in several trim levels. But few did. Of the nearly 251,000 Coronets sold in 1966, only 738 were Hemi equipped. The rarest is the Hemi-powered Coronet 440 convertible (440 was the trim level not the engine). Only six were built.

The cars’ value today? That’s hard to pin down, but a 1966 Hemi Coronet 500 convertible (500 was the fancier trim level)—one of 12 convertibles built that year with a four-speed transmission—sold at RM’s 2017 Arizona auction in 2017 for $176,000.

1970 Dodge Challenger R/T Convertible

1970 Dodge Challenger R/T Convertible green 3/4 front
Mecum
1970 Dodge Challenger R/T Convertible

This is by far the sexiest and most valuable car on this list. In 1970, the new Dodge Challenger was introduced to fdo battle with the Chevy Camaro and Ford Mustang. It was offered as a two-door hardtop or convertible and the Hemi was optional. That year, well over 200 Hemi hardtops were sold, but only nine convertibles—four with the Torqueflite automatic and five four-speed cars. They sell for big bucks today and can surpass $1 million for the right car in the right room. A #1 condition car with four-speed and optional Shaker hood scoop is valued at about $1,250,000, which is down about 10 percent over the last 18 months.

Incredibly, it’s also a fraction of the value enjoyed by the 11 Hemi ‘Cuda convertibles built in 1971, the final year of Hemi production. Of the 11, only two got four-speeds and that legendary Pistol Grip shifter. These are multimillion dollar cars and remain the most valuable of all American muscle cars. A 1971 Hemi ‘’Cuda convertible is worth $1.55 million in #4 condition—that’s described as “complete and functional but flawed with pitted chrome, a split dash. and dented bodywork.” A #1-condition car is valued at $3,150,000. One of the two four-speed cars, said to be a numbers matching example, sold for a world record $3.5M at Mecum 2014 Seattle auction.