Written by Eric Becker

There’s something inherently satisfying about a car with a genuine motorsports pedigree. Cars first slated to prove their mettle on the circuit feel a cut above their more common siblings. Often, the sanctioning body of a racing series enforces a rule that manufacturers must make their top-tier racing car available to the roadgoing public, a process termed “homologation.” Homologation has gifted the motoring world with some of the finest machinery in both road and track history. Among them is Chrysler’s fabled 426 HEMI, nicknamed the “Elephant” for its immense size and power. The engine’s mythos has long been synonymous with American horsepower and emblematic of Detroit Muscle.

Tom Hoover, the “Father of the HEMI,” at the 2014 Mopar Mile-High NHRA Nationals, where he served as grand marshal and was presented with the Mopar President’s Award, joining a select group to receive the prestigious honor. (Photo courtesy FCA Media)

Chrysler’s second-generation HEMI was bred specifically to bring Chrysler success in NASCAR. Chrysler’s then president, Lynn Townsend, understood the importance of the “Win on Sunday, Sell on Monday” intonation, and tasked Tom Hoover and a skunkworks team of engineers to put Mopar firmly in the victory lane. Development began in April 1963. Hoover, in his role as Racing Program Coordinator, surmised that the most efficient way to save cost and produce power was to use the 426ci (7.0-liter) RB variant of Chrysler’s B-Series big block. He then adapted the first-generation of Chrysler’s successful hemispherical-shaped combustion chamber to work with the RB’s already stout bottom end. In just over 10 months, Hoover and his team had done it. The A-864 engine roared to life on the dyno in December 1963, and Hoover justifiably earned the title as “Father of the HEMI.”

Debuting in 1964, Chrysler’s big-block 426 HEMI V8 entered the world as an unapologetic race engine, designed for the sole purpose of conquering the banks and ovals of Daytona and Talladega. And conquer it did. Four of the top five finishers sported Chrysler’s new HEMI, with a trio of Plymouth Belvederes sweeping the podium, led by the famed Richard Petty standing atop. Petty dominantly took the win by over a lap, and the 426 would propel him to nine victories and his maiden NASCAR championship.

The 1963-65 HEMI engine. (Photo courtesy FCA Media)

The HEMI’s dominance during the 1964 season would draw the ire of NASCAR officials. The series would ultimately ban the Elephant, deeming it not a true production engine. NASCAR officials stipulated a homologation requirement for Chrysler’s HEMI engine to continue in the series. Chrysler, for its part, would have to forego production of a select few blueprinted HEMI engines, and manufacture the Elephant by the thousands for consumption by the general public.

The result was that the next NASCAR season (1965) began and ended without Chrysler on the track.

Fortunately, the engine’s development team had a vision and goal beyond NASCAR. The team optimized Elephant-powered cars for drag racing, where the 426 proved a sensation, dominating the 1964 Super Stock class with ultra-lightweight factory cars – available, by the way, for order at the showroom. Designated with the code A-864, the package was initially available for 1964 and could be had on either Plymouth and Dodge models. In ’65 the designation was changed to A-990, and was available for the Dodge Coronet and Plymouth Belvedere.

1966 Street HEMI. (Photo courtesy FCA Media)

While produced in low volumes – 112 for the A-864, and just over 200 for the A-990 – the turnkey drag racers paved the way for the race-inspired public to get their hands on the Elephant. The blacktop was never quite the same. An April 1, 1965, confidential price bulletin warned, “This model is intended for use in supervised acceleration trials and is not intended for highway or general passenger car use.”

For the next model year in 1966, Chrysler responded by offering a slightly tuned-down version of the 426 HEMI, known as the Street HEMI. The engine sported a milder camshaft and lower compression ratio for a more forgiving on-road stop-and-go performance. The Street HEMI was outfitted with a dual four-barrel carburetor mounted on an aluminum dual-plane intake manifold. The engine’s advertised horsepower and torque were 425hp and 490 ft/lbs, though most considered the actual horsepower output closer to the 500 number. With the 426 now appearing as an option in Plymouth Belvedere, Dodge Coronet and Charger series, the Elephant returned to NASCAR competition. Yet perhaps more importantly, the rules of homologation begat the true beginning of the muscle car era.

Still winning: Jimmy Daniels raced the Super Stock 1968 Dodge Dart to his fourth consecutive NHRA Dodge HEMI Challenge victory during the U.S. Nationals at Lucas Oil Raceway at Indianapolis in 2019. (Photo courtesy FCA Media)

Another by-product of homologation was Chrysler’s Super Stock competition package. Tailored to the regulations of the National Hot Rod Association class of the same name, was available for both Dodges and Plymouths in 1967. At least 50 cars had to be built to meet series homologation requirements, so around 55 Plymouth Belvedere IIs (RO23) and 50 Dodge Coronets (WO23) were duly manufactured (the true number actually may have been less). The RO23 and WO23 cars were the end of an era – the final purpose-built Super Stockers to come directly from a Chrysler production line.

Because Dodge and Plymouth wanted to own the Super Stock drag racing class for the 1968 season, Chrysler subcontracted with Hurst Performance. These new cars were so radical they could not be built on a Chrysler production assembly line. Hurst would take partially assembled big-block A-bodies and install high-compression 426 HEMI engines, lightweight body panels and stripped-down interiors – resulting in what was known as the LO23 Dodge Darts and BO29 Plymouth Barracudas. These Super Stock models are among the most important cars in Chrysler’s legendary performance programs; some of the 1968 Super Stocks still hold drag racing records in the stock class.

The 426 HEMI remained available as an option until 1971, when it passed into history, leaving one of American Muscle’s most stout and prolific legacies. While only 10,904 Elephant HEMI-powered cars rolled out of the Chrysler factories, the motoring world is richer for these examples. As ardent admirers of the HEMI, more than a few have rumbled their way across the Barrett-Jackson auction block – the high demand reflecting a change in the collector car hobby that began more than a decade ago. More people keen on acquiring the rare muscle car of their dreams were coming of age. Barrett-Jackson led the trend, and the 426 HEMI was the prime power plant on everyone’s list. Here are a few of our favorites.

1966 DODGE HEMI CORONET DELUXE 4-DOOR SEDAN

Billed as the “world’s rarest” 426 HEMI, this Coronet is one of only five 4-doors built. The majority of 426 Elephant HEMI-equipped Coronets were 2-doors and convertibles. Of the five cars, one was exported to Finland, one to Canada and three stayed in the American market. Currently, one of the 426 4-door Coronets resides in “Big Daddy” Don Garlits’ Museum of Drag Racing. This car could easily be viewed as one of the world’s first ever super-sedans and sold for $660,000 at the 2007 Scottsdale Auction.

1966 PLYMOUTH BELVEDERE II

Perhaps one of the most understated powerhouses to ever leave the St. Louis factory, this ’66 Belvedere is kitted with the monster HEMI engine, backed by a 4-speed manual transmission and DANA 60 rear end. Finished in red-on-red, the Belvedere crossed the block at the 2008 Scottsdale Auction and met a final price of $82,500.

1967 DODGE HEMI CORONET R/T CONVERTIBLE

1967 was the first year for the “Road & Track” or, more commonly, the R/T option. This Coronet R/T Convertible rumbled across the block at the Scottsdale 35th Anniversary Auction in 2006, selling for a final price of $269,500. The exceedingly rare Coronet is of just three convertibles fitted with the 426 and one of just two fitted with a 4-speed manual gearbox.

1967 PLYMOUTH BELEVEDERE HEMI SUPER STOCK

Crossing the block at the 2016 Scottsdale Auction, this 1967 Plymouth Belvedere II Super Stock is one of the ultra-rare RO23 HEMI-powered factory racers produced. This Belvedere is one of just 38 equipped with the optional factory reverse shift pattern automatic transmission. Delivered race-ready without heater, radio, body insulation, carpet underlay or seam sealer, the RO23s were several pounds lighter than stock models. The 426 HEMI has tuned twin Carter 4-barrel carburetors fed by a massive Ram Air hood scoop. It is officially rated at 425hp; it most certainly made more. The race-bred piece of HEMI and Mopar history met a final price of $84,700.

1968 DODGE HEMI DART

Formerly owned by Lou Mancini of Mancini Racing and the Chrysler Corporation, this 1968 HEMI Dodge Dart was built to race in the Super Stock manufacturer wars of the late 1960s. This is No. 5 of 56 in the Chrysler Registry and was fitted with a 426 HEMI engine and automatic transmission installed by the Hurst Corporation. The ’68 Dart crossed the block at the 2006 Scottsdale 35th Anniversary Auction with a final price of $330,000.

1970 PLYMOUTH HEMI ’CUDA CONVERTIBLE

Barrett-Jackson’s 35th Anniversary Auction in January 2006 could easily be touted as kicking off the year of the 426 HEMI – and one of the crown jewels of that event would easily be this 1970 HEMI ’Cuda convertible. One of only 14 produced in 1970, this ’Cuda commanded the stage and brought in an astounding final price of $2.2 million, making it among the most valuable muscle cars ever sold at auction. The one-of-a-kind ‘Cuda is the only HEMI convertible finished in High Impact Vitamin C. Power comes from a matching-numbers 426ci Elephant HEMI backed by an A727 TorqueFlite automatic transmission. Additional features included the A32 Super Performance Axle Package with Sure-Grip 4:10 gears and B51 power brake package. If the open-top thrills and roar of the V8 aren’t enough, the ’Cuda also came with an 8-track player. Not that you’d need it.

1970 PLYMOUTH HEMI SUPERBIRD

No list of legendary HEMIs would be complete without the Superbird. This 1970 example is reported as No. 25 of 78 HEMI Superbirds and features include the original 426ci HEMI engine with dual four-barrel carburetors mated to a727 TorqueFlite automatic with the A36 performance axle package. Beautifully refinished in Alpine White, this Superbird crossed the block at the 2014 Scottsdale Auction and went to its new home for $550,000.

1970 PLYMOUTH HEMI ROAD RUNNER

One of only 44 HEMI 4-speed coupes produced, this Road Runner features an Air Grabber hood, Dana 3.54-ratio rear end with Track Pak, power steering and power disc brakes. The interior features the uncommon deluxe Saddle and tan upholstery. This rare Road Runner rides on Rally wheels with Goodyear Polyglas tires. After an outstanding ground-up restoration, this rock-solid HEMI Road Runner was beautifully refinished in its original shade of High Impact Lemon Twist Yellow paint. The Road Runner scored a final price of $214,500 at the 2018 Scottsdale Auction.

1971 PLYMOUTH HEMI ’CUDA CONVERTIBLE

Today, the HEMI remains a true automotive milestone and extraordinary example of Detroit Muscle at its finest. We thought it only fitting to round out our list with one of rarest examples of the breed. Crossing the block during the 2013 Scottsdale Auction, this ’71 HEMI ’Cuda convertible is one of only 11 produced and the only one finished in In-Violet (Plymouth’s version of Plum Crazy). The purple-colored ’Cuda would meet a final price of $1.32 million and has long been a fan favorite.

It may have been a nuisance at the time and delivered quite the fracas in the NASCAR paddock, but thanks to the rules of homologation the 426 HEMI wasn’t solely relegated to the track ‒ it can also be found in our garages and on the auction block.