Storied Hemi marks 50 years
There’s just no replacement for displacement
The Republic P-47 Thunderbolt was already a hell of an aircraft — and then Chrysler crammed a Hemi into it. The biggest piston-powered, single-engine fighter ever built, the “Jug” (for Juggernaut) was nearly indestructible.
Into the nose of this colossal single-seat machine, capable of hauling half the bomb load of a B-17 Flying Fortress, the wartime Chrysler company inserted a 16-cylinder inverted-V engine displacing 36 litres and weighing over a metric ton. It was a Hemi, one of the first such engines built by Chrysler, and its turbocharged 2,500-horsepower thrust the P-47 past the 500-mile-an-hour mark. Sadly, the Chrysler-powered P-47 showed up too late to be any use in the Second World War.
Happily for anyone with gasoline in their veins and a close-ratio gearbox for a heart, it wasn’t the last time Chrysler’s Hemi would get a chance at battle.
This year marks a half-century since the legendary 426 Hemi engine showed up and decimated the competition. The Hemi name is derived this way: remove the heads on any one of these engines and you’ll find a row of combustion chambers shaped like a dome — a hemisphere.
With a spark plug centrally located for a nice even burn and a pair of valves, a hemispherical combustion chamber lets an engine make decent horsepower levels.
The Chrysler group built and developed a whole series of engines of differing displacements and cylinder-numbers right through the 1950s. Bean-counting executives decided to shelve further development of these Hemi engines, and phased out first-generation motors by 1958. The iconic Hemi name wouldn’t come until 1964, with the racing 426 — about seven litres of displacement.
Because of the way the large valves are situated inside the combustion chamber,a Hemi can ingest air and expel exhaust gases with greater speed than a conventional design. While Chrysler’s “Wedge” engine was already enjoying drag-racing success, the 426 Hemi racing engine it created for NASCAR had a few issues.
In April of 1963, Chrysler gave the go-ahead to its engineering team to try adapting Hemi technology to its 426 Wedge big block. They trademarked the “Hemi” name and set a target to compete at the Daytona 500 in the spring of 1964.
Between the enthusiastic gearheads and the morecareful eggheads on the team, a prototype engine ran under its own power in December of ’63. Shoehorning this behemoth into a race-prepped chassis was easy but under stress, the engines were cracking their cylinder bores.
With the Daytona 500 looming in three weeks, engineers shuttled between the engine forges in Detroit and the speedway in Florida, hauling parts and engines overnight. Race day came: February 23rd, 1964. On the racetrack, the elephant roared its battle cry for the first time.
As the crowd watched, open-mouthed, the Hemipowered Plymouths bellowed past the checkered flag 1–2–3–4. The pack was led by one Richard Petty, a NASCAR driver who would come to be called“The King.” It was the first of seven wins he’d have at Daytona, his first ride on the way to becoming the most successful NASCAR racer of all time, equalled only by Dale Earnhardt. And a Hemi got him his first Daytona checkered flag.
After the fleet of Hemipowered racers decimated the field repeatedly over the season, NASCAR banned the engine — to the later joy of car enthusiasts. NASCAR’s specific objection was the race-only status of the 426, which forced Chrysler to develop something they called the Street Hemi — a detuned version. And while that happened, the 426 took to dragracing, where it racked up huge success.
The first civilian-spec 426 Hemi engines showed up in 1966 with the Dodge Coronet and Charger, and the Plymouth Belvedere as part of the options list.
Original 426 Hem i Chrysler-group cars are rare, collectible, and expensive. Numbers-matching examples routinely sell in the quarter-million-dollar range, and a rare Hemi Barracuda convertible recently sold for nearly $3 million.