Written by Eric Becker
What better way is there to define American horsepower than the simple word “HEMI?” Synonymous with Detroit iron, Mopar muscle and on-track dominance, the HEMI would cement Chrysler as a major player in the muscle car wars of the 1960s. It also left us with the enduring tagline, “That thing got a HEMI?”
You’d be excused for thinking Chrysler was the originator of the hemispherical combustion chamber (thankfully abbreviated to HEMI), but that honor cannot be bestowed on any one manufacturer or inventor. Early designs can be traced as far back as 1901, with Belgian automaker Pipe being amongst the first. Dozens of manufacturers experimented with the bisected baseball-esque combustion chamber. Fiat, Peugeot and Alfa Romeo used them in early Grand Prix cars, and, in the aeronautics realm, Pratt & Whitney used the design in their radial engines.
With good reason, the hemispherical combustion chamber sought to maximize the volume of air/fuel mixture while minimizing the surface area, and heat loss, within the combustion chamber. An overhead valve design placed the spark plugs top center, allowing greater air/fuel volume in a smaller space. HEMI meant more power, which in any – and all – circumstances, is a good thing.
Chrysler’s first HEMI wouldn’t begin to take shape until the interwar period. Developed for aeronautic use, the marque’s top engineers crafted an inverted V16. Slated to power the P-47 Thunderbolt fighter plane, the gargantuan V16, known as XIV-2220, measured 2,220ci (36.4 liters), produced 2,500hp and exceeded 500 mph during test flights, making it one of the fastest piston-driven aircraft of the period. Regrettably, this engine never found its way into production, as it was preempted by the era of jet propulsion.
But that wasn’t the end of it.
Chrysler’s engineers recognized a “silver lining,” taking what they’d learned in service of the war effort and applying it to road-going automobiles. The result did not disappoint. Chrysler had changed the game, unveiling its new hemispherical head overhead-valve V8 to the world in 1951, and with it the first-generation HEMI V8 was born.
Chrysler’s HEMI has been around some 70 years now across three distinctive generations. The family of HEMI engines have powered some absolute marvels that have rumbled their way across the auction block. Barrett-Jackson is no stranger to the HEMI and could even be described as an ardent admirer. HEMI-powered machines from all eras have shattered expectations and set records. We thought it only fitting to delve into but a snippet of the greatest HEMIs to roll out of Detroit and power some of the great coachworks and concepts in Mopar history.
First Generation: The Italian Connection
When it first launched in 1951 the HEMI wasn’t called the HEMI; that designation wouldn’t arrive until the second generation. Instead, Chrysler opted for the hyper-masculine name FirePower. The over-square engine would sit atop the first generation’s hierarchy and power Chrysler’s most elite offerings. 1951 would also see Chrysler partner with the Turin, Italy-based coachbuilder Ghia. The pairing presented the automotive world with masterful works of design, combining the brash styling cues of Eisenhower-era America with subdued European fluidity. These highly sought-after examples are nothing less than masterful. As the ’50s progressed, Chrysler would advance the notion of the “concept car,” ensuring that the dream car would correlate to each of its divisions and sport the very latest in technological achievement. In terms of powertrain, these cars represent the first generation of HEMIs.
Penned by Ghia’s Mario Boano in collaboration with the great Virgil Exner, the 1952 Chrysler d’Elegance sat atop a shortened New Yorker chassis, and was deemed one of the greatest show cars in automotive history. Clad in a beautiful maroon finish, the d’Elegance would heavily influence Chrysler’s “letter” car designated series, remaining a stylistic icon and one of the hallmarks of Exner’s design legacy. Initially powered by the 331ci FirePower V8, that engine would be replaced during the car’s storied ownership, and the larger 354ci power plant would sit under the hood. Crossing the block at the 2006 35th Anniversary Scottsdale Auction and selling for an eye watering final price of $1.21 million, this one-off is one of America’s most celebrated automobiles.
Chrysler’s engineers would continue to develop the FirePower HEMI, as the flagship motor for the brand. The new-for-1957 392ci would become a mainstay of period drag racers and go on to power many of “Big Daddy” Don Garlits’ dragsters. The largest and most powerful iteration of the first-generation HEMI would find itself powering another Virgil Exner-penned and Ghia-bodied design. The 1956 Dart concept would later be updated and renamed the Dart Diablo, featuring a more realized version of Exner’s own “Forward Look,” keeping it more in line with the aesthetic of other Chryslers of the era. The streamlined bodywork could easily be mistaken for that of a period spaceship – no doubt due to the fact the car was designed in a wind tunnel on Exner’s own personal drawing board. Based on 1956 Chrysler 300 chassis, the Diablo was massive in size; just shy of 21 feet in total length. Crossing the block at the 2013 Scottsdale Auction, the Diablo concept car would go to its new home for a final price of $1.375 million.
Chrysler’s family of HEMI engines would carry over into the DeSoto brand, descriptively named the Fire Dome. Launched in 1952, the 276.1ci Fire Dome was rated at 170hp and 255 lbs/ft of torque, an ample amount of power for any Grand Tourer of the period. The Fire Dome HEMI would find its way under the hood of another stunning Ghia-bodied Mopar, the 1954 DeSoto Adventurer II. A truly spectacular design, Ghia’s Giovanni Savonuzzi invoked his “Supersonic” design language that would be lightly reworked by Chrysler Chief of Advanced Design Virgil Exner. The roadworthy concept was chosen as one of the 10 greatest concepts ever built, and upon close examination it’s easy to see why. The bold yet refined lines illustrate just how fastidious and perfection-minded the designers were. The remarkable DeSoto crossed the Barrett-Jackson block at the 2012 Scottsdale Auction and brought a jaw-dropping final price of $1.43 million.
In 1953, Dodge unveiled its Firearrow, a sleek, jet-age roadster providing a preview of how art and science would be integrated into the next-generation automobile. The initial concept became so successful that a full family of Firearrow concept cars would follow. Barrett-Jackson had the privilege of auctioning Firearrows II and IV, the convertible pairing of the quartet. Both cars were penned and built by Ghia, with oversight by the venerable Virgil Exner. The Firearrows featured Dodge’s 241ci Red Ram HEMI engine. The two concepts sold as a pair for $2.2 million at the 2007 Scottsdale Auction.
The first-generation HEMI powered some of the most striking and significant concepts in Mopar history. The engines born from experience in working with the military would live on, powering hundreds of thousands of Chrysler automobiles on the road and on the racetrack.
For a few years, the HEMI would be shelved in favor of different designs. But by 1964 the hemispherical cylinder head would be back. The second generation “Elephant” HEMI (story coming soon!) would ingrain the name into the automotive lexicon forever.