See the historic hemi-engine and how it evolved
Chrysler’s first Hemi Engine dates back to 1951 and is currently enjoying revivals across the Stellantis lineup.
- The HEMI engine is named after the hemispherical piston head of the engine.
- The Chrysler brand popularized the name and registered its trademark, but in the early 1900s a Hemi-style engine was developed.
- Hemi has been in the car scene for generations, in a variety of cars since it first appeared in the car scene in 1951.
If you’re at a Ram dealer and you’re asking, “Did you get a Hemi?”, the odds are that you do. It may not have been that way a year ago.
Stellantis sub-brands – Chrysler Corporation, previously including name plates such as Dodge, Jeep, Fiat, Ram, and more, highlights Hemi in 2025, returning a long-term V-8 engine to the 1500 lightweight truck class, and registering the Hemi Standard with all Dodge Durangos. Even Jeep suggests the availability of more hemis in its products, including Jeep’s pickup truck, which is the gladiator.
Hemi’s current home is under the hood of some of the biggest and most powerful products of Stella Lantis, but the engine holds some of the most iconic vehicles in Chrysler history. As Ram celebrates his return to Hemi, we can look back at the life of Motor, who experienced several generations, cancellations, updates and revivals from 1951 to 2025.
But first, there is a very short lesson in engineering.
What makes Hemi hemi?
The name Hemi is from HemiA spherical (semicircular) piston head used in the engine of the same name. The round piston heads slot into a rounded chamber, providing higher efficiency, with less energy, less energy, while the fuel was burning while the fuel was burning.
Of course, Chrysler Corporation popularized the name and registered its trademark, but many car manufacturers use hemispherical combustion chambers in their engines. In fact, one of the earliest versions of the engine with a hemispherical piston head came from another Michigan automaker.
Welch, a short-lived Pontiac-based automaker, used technology to bolster the 1908 Model 4-L. Many automakers messed around with hemispherical piston designs in the early 20th century. This includes Chrysler’s recently adopted brothers, Alfa Romeo, Fiat and Peugeot.
First generation: 1951 firepower V-8
Chrysler’s hemitech was first used by the company to power the XIV-2220, a V16 fighter engine developed at the tail end of World War II. Although the engine had never seen its use during wartime, Chrysler engineers returned to postwar America and had ideas on how to make a powerful and efficient engine with a hemispherical combustion chamber.
Introducing in 1951 and inspired by a work carried out in fighter jets, Chrysler’s first mass-produced hemi was called firepower.
The powerful V-8 engine was used to power Chrysler New Yorkers, Imperials and Saratogas in the 1950s. With 331 cubic inches and 180 horsepower, the engine provided great propulsion to Chrysler’s mainstream offering, surpassing most of its competition.
Dodge adapted firepower to a 1953 Red Rum pickup truck, and DeSoto, a now-defunct Chrysler imprint, also began using the engine, calling it a shooting.
The firepower engine was considered both powerful daily drivers and weekend racers as the city developed the street racing culture.
By the mid-50s, Chrysler had bolstered the 331-cubic-inch engine to a 392-cubic-inch V-8, stuffed it under the New Yorker and Empire hood.
However, by 1958, the thermal engine was halted as automotive regulators had become interested in relation to large-scale car brand races.
Second generation: 1964 426 Hemi
For the old gearhead, the 426 cubic inch hemi, first produced in 1964, is one of the largest engines ever.
It started out as a racing engine limited to NASCAR only, and was driven to Richard Petty’s Plymouth Belvidere on the NASCAR circuit. 426 Race Hemi was so powerful that other race teams asked NASCAR to ban the engine.
By 1965, a slightly tuned 426 was revealed as the “Hemi Street Engine” and was equipped with late ’60s street racing machines, including the Dodge Coronet, Plymouth Belvidere, Plymouth Satellite, Plymouth Barracuda and the legendary Dodge Charger.
The loudly grumbling street hemi provided 425 horsepower to the public, while the more robust 426 race hemi tore NASCAR and the National Hot Rod Associations in the early 70s.
Chrysler stopped production of the 426 HEMI in 1971 and did not sell the car using the HEMI name for another decade.
Vehicles like Dodge Aries and Plymouth relied on, were successful sales, often called the one that saved Chrysler’s bacon, but were a tough departure from Hemis in the ’70s. Hemi designation was primarily a marketing tool. The small outsourced engine produced only 96 horsepower.
Third Generation: Hemilibival
After 16 years of dormancy, the third generation of Hemi Engines debuted in the 2003 model year as a new powertrain for the RAM 1500.
It was a hit.
The rum pickup with Hemi became a cultural touchpoint through the clever “Tangan Gets Hemi”. Advertising campaign. The truck was equipped with a redesigned 5.7L HEMI V-8, the 5.7L HEMI V-8, which produced 345 horsepower.
The third generation engine carried all names and Hemi bravery without Hemi technology. Current Hemis no longer use the appropriate hemispherical piston head design, instead using flat piston heads that are more efficient and less exhausted.
After the revival of Hemi in 2003, the Chrysler brand slowly began to launch Hemi Bonanza. In 2005, the company launched the Hemi SRT-8 with 425 horsepower, matching the power output of the legendary second-generation engine. Soon after that, 392 cubic inches of Hemi gave customers 470 horsepower from the lot.
Some third generation Hemi has appeared in the Chrysler 300, Dodge Magnum, Charger, Challenger, Durangos, Jeep Grand Cherokee and Gladiators.
And in 2015, Dodge launched its first Hemi engine without natural aspiration. Dodge chased the Hellcat with a more powerful demon and a huge 1000 horsepower crate engine called Hellephant.
In 2024, RAM announced that it would slow production of HEMI engines on its 1500 series pickup trucks, but this change lasted only a year before the company ran a frenzy of engineering campaign to reform the 5.7L version of the 2026 model.
Outside the Sterling Heights assembly plant, where the lamb truck is made, a large black and yellow banner hangs loudly and proudly messages.
“The Hemi V-8 is back.”
Liam Rappleye covers Stellantis and UAW. Please contact him: lrappleye@freepress.com.
