The HEMI V8 engine began life in 1950, spanning three generations across a whopping 70+ years! The Chrysler Corporation initially manufactured its notorious V8 engine to tackle GM’s 5.0-liter Rocket 88 performance V8 and Ford’s disastrous Flathead V8 engine. Despite having a mountain to climb, Chrysler had a trick up their sleeve.The HEMI V8 engine, past and present, operates with eight hemispherical-shaped combustion chambers, allowing Chrysler to fit larger valves, increasing power. A hemispherical design also reduces the surface area within the chamber, limiting heat loss. In turn, the dependable HEMI V8 design transports its superior air-fuel mixture far more efficiently than its fellow V8 cousins, making the HEMI V8 engine the most efficient way to develop large amounts of power with a V8 format.Sadly, the revered HEMI V8 formula will retire at the end of 2023 as Dodge looks to switch to a more efficient propulsion method to replace today’s increasingly troublesome V8 engines. Be that as it may, now is the perfect time to cast our beady eyes across the HEMI V8 engine’s incredible lifespan, powering automotive icons from Dodge and Plymouth, all the way down to the grunty pickups from RAM and questionable SUVs from Jeep.
1951-1958: First-Generation Chrysler Firepower HEMI V8 Engine
The first ever HEMI V8 arrived with a different name, the Firepower V8. Chrysler unleashed their original HEMI V8 engine in 1951 due to their experience building hemispherical engines for the military. The 331 (5.4-liter) V8 developed 180 hp, powering iconic Chrysler nameplates such as the New Yorker and even went on to feature across the failed Imperial marque. It’s worth noting that Ford’s Flathead V8 produced around 110 hp, and GM’s Rocket 88 could reach 135 ponies in 1951. Meaning, Chrysler had the most powerful V8 engine among the big three.Perhaps even more interesting, the Firepower V8 became the chosen power source for the world’s loudest siren! The Chrysler Air Raid Siren, built between 1952-1957, produces a brain-melting 138 decibels, drawing power from a 5.4-liter Firepower HEMI V8 engine. Sirens aside, only three of Chrysler’s four automotive brands used the Firepower V8 HEMI engine.Chrysler and their later “Imperial” luxury marque operated with Firepower V8 engines ranging from 5.4-6.4 liters in size. The most powerful arrived in 1957, developing an incredible 375 hp aboard the Chrysler 300, displacing 6.4 liters. Chrysler’s efforts quickly became a favorite for dragsters of the era thanks to their Carter WCFB dual four-barrel carburetors setup and hydraulic valve lifters, allowing their 1957 luxury 300 models to reach the lofty heights of 375 hp and 420 lb-ft of torque! In fact, the Chrysler 300 could go from 0-60 mph in around eight seconds in 1957!
1951-1958: DeSoto And Dodge HEMI V8 Engines
DeSoto and Dodge also got their greasy paws on the Firepower HEMI V8 engine. DeSoto rebranded the V8 engine, the “Firedome” V8, and remained a step behind the flagship Chrysler cars. The DeSoto Firedome V8 had a maximum power output of 345 hp from their 1957 5.6-liter iteration of the HEMI V8 engine.Ironically, by today’s standards, Dodge featured the weakest version of the first-gen HEMI V8, maxing out with their “Super Red Ram” HEMI developing just 260 hp aboard their Coronet and Royale models.
1964: Second-Generation 426 “Elephant” HEMI V8 Engine
The most fabled of HEMI engines, the 426 HEMI, saw a return of the hemispherical V8 engine in 1964 solely for racing purposes. Despite being the second HEMI V8 engine, the 7.0-liter titan was the first to wear the “HEMI V8” name within Chrysler marketing materials.Chrysler’s 426 HEMI V8 quickly got to work, dominating the NASCAR championship at the hands of racing royalty such as Richard Petty and David Pearson. Chrysler fitted the aptly named “Elephant” to Plymouth Belvedere models initially, and luckily for gearheads, NASCAR quickly had the engine banned.
Homologation Street Hemi (7.0-Liter)
Chrysler’s 425 hp and 490 lb-ft of torque second-generation HEMI engines were too much for NASCAR. Sadly, due to complaints from Ford and a change in homologation rules, the vast 800 lb V8 engine got pushed out of the 1965 NASCAR season, leading Chrysler to create production variants of the notorious HEMI V8 to return to the track. Luckily for us, that resulted in the A102 Street HEMI, responsible for powering some of the most prolific muscle cars between 1966 and 1971.Chrysler’s Street HEMI V8 arrived with a pair of four-barrel AFB carburetors and a reduced compression ratio of 10.25:1 compared to 12.5:1 produced by its racing counterpart. By producing a street version of their notorious V8 engine, the HEMI returned to racing for the 1966 season.Some of the most notable muscle cars featuring the 426 HEMI are scarce gems today, such as the Dodge Dart HEMI, Dodge Charger R/T, Plymouth Superbird, and Plymouth Cuda. The 426 HEMI engine arrived in small numbers, rocketing Mopar’s greatest muscle cars from 0-60 mph in around five seconds, while shattering the quarter mile in under 14 seconds. Unfortunately, a little-known event called the “oil crisis” retired the legendary 426 HEMI V8 post-1971.
2003: Third-Generation “Eagle” HEMI V8
Back in 2003, while under the stewardship of DaimlerChrysler, the HEMI V8 engine made an astonishing return, replacing the Magnum engine series to return Chrysler’s character of old. The “Eagle” HEMI featured a two-valve pushrod design partnered with an electronic throttle control system, developing a hearty 345 hp from its 5.7-liter displacement.The returning HEMI eventually grew to 6.1 liters for SRT-branded models, arriving with a forged crankshaft and lighter pistons. Further upgrades to the 6.1-liter saw a cast aluminum intake manifold and a wholly revised coolant channeling system to aid the performance block. However, best of all, the 6.1-liter HEMI V8 produced a somewhat familiar 425 hp at 6,200 RPM, just like its 426 HEMI predecessor
2011: Apache HEMI V8
Another engine condemned, the “Apache” HEMI V8, arrived in 2011 and featured onboard a limited number of “392 HEMI” badged cars. This 6.4-liter iteration of the Eagle HEMI pays homage to the HEMI V8 engines of old, developing a hearty 525 hp thanks to its additional high-strength forged aluminum pistons. The 392 HEMI replaced the 6.1-liter performance V8, going on to feature within limited SRT models, such as the Durango and Challenger SRT 392 models. In fact, the Apache HEMI even replaced the 5.7-liter HEMI engine across Cab-Chassis RAM Pickup trucks post-2016.
There is another automobile manufacturer who created a Hemi V8 engine many years before Chrysler, it was even equipped with overhead cams. That company is Tatra, made in what is now the Czech Republic. Tatra’s first Hemi V8 was in the Type 77 & 77a cars, made in 1934-38, Then in the Type 87 thru 1950. An all new Tatra Hemi V8 saw production starting in 1956, and was used in the Type 603 models thru 1975. [I’ve owned several of the 603 cars.] Tatra also produced a newer car called the Type 613 starting in 1969 and built until 1997. I can’t find a decent diagram of the 613 motor to be 100% sure, but I do believe that DOHC engine is also a Hemi-head V8. Larger versions of the Hemi-V8 were constructed for Tatra’s trucks as well.
Part 2 to follow;