Chrysler Hemi engine. The Chrysler Hemi engine, known by the trademark Hemi or HEMI, refers to a series of high-performance American overhead valve V8 engines built by Chrysler with hemispherical combustion chambers. Three generations have been produced: the FirePower series (with displacements from  to ) from 1951 to 1958; a famed  race and street engine from 1964-1971; and family of advanced Hemis (displacing between   from 2003 to the present.

Although Chrysler is most identified with the use of "Hemi" as a marketing term, many other auto manufacturers have incorporated similar cylinder head designs. The engine block and cylinder heads were cast and manufactured at Indianapolis Foundry.

During the 1970s and 1980s, Chrysler also applied the term Hemi to their Australian-made Hemi-6 Engine, and a 4-cylinder Mitsubishi 2.6L engine installed in various North American market vehicles.

Design

The main advantage of a hemi head engine over other head designs is power.  In return, hemi head engines tend to have complex valve trains, are expensive to build, and both larger and heavier than conventional designs.

A hemispherical combustion chamber is an efficient shape, with an excellent surface-to-volume ratio,  and room for two large valves. However, it allows no more than two valves per cylinder, and these large valves are necessarily heavier than in a multi-valve engine. The intake and exhaust valves lie on opposite sides of the chamber and necessitate a "cross-flow" head design. As the combustion chamber is a partial hemisphere, a flat-topped piston would yield too low a compression ratio unless a very long stroke is used, so to attain the desired compression ratio the piston crown is domed to protrude into the head at top dead center. The result is a combustion chamber in the shape of the space between where the domed piston stops and the dome shape in the head receiving it.

The hemi-head design places the spark plug at or near the center of the chamber to promote a strong flame front. However, if the hemi-head hemisphere is of equal diameter to the piston, there is minimal squish for proper turbulence to mix fuel and air thoroughly. Thus, hemi-heads, because of their lack of squish, are more sensitive to fuel octane rating; a given compression ratio will require a higher octane rating to avoid pre-ignition in a hemi engine than in some conventional engine designs such as the wedge and bathtub.

The hemi head always has intake and exhaust valve stems that point in different directions, requiring a large, wide cylinder head and complex rocker arm geometry in both cam-in-block and single overhead cam engines (dual overhead cam engines may not have rocker arms). This adds to the overall width of the engine, limiting the vehicles in which it can be installed.

Significant challenges in the commercialization of engine designs using hemispherical chambers revolved around the valve actuation, specifically how to make it effective, efficient, and reliable at an acceptable cost. This complexity was referenced early in Chrysler's development of their 1950s hemi engine: the head was referred to in company advertising as the Double Rocker Shaft head.

First generation: FirePower 1951–1958 
Chrysler developed its first experimental hemi engine for the Republic P-47 Thunderbolt fighter aircraft. The XIV-2220 was an inverted V16 rated at . The P-47 was already in production with a Pratt & Whitney radial engine when the XIV-2220 flew successfully in trials in 1945 as a possible upgrade, but the war was winding down and it did not go into production. However, the exercise gave Chrysler engineers valuable research and development experience with two-valve hemi combustion chamber dynamics and parameters.

In addition to the aircraft engine, Chrysler and Continental worked together to develop the air-cooled AV-1790-5B V12 Hemi engine used in the M47 Patton tank.

Chrysler applied their military experience with the hemispherical combustion chamber to its first automobile engine, an overhead-valve V8 engine released under the name FirePower, not "Hemi," in 1950 for the 1951 model year. The first version of the FirePower engine had a displacement of  and produced . Eventually, three of the four Chrysler divisions had their own version of the FirePower engine, with different displacements and designations, and having almost no parts in common. This lack of commonality was due in part to the three engine versions using different bore pitches (the center-to-center distance between adjacent cylinders). Chrysler and Imperial called their versions the FirePower. DeSoto called theirs the FireDome. Dodge had a smaller version, known as the Red Ram. Only Plymouth did not have a version, but retained the Dodge poly-head engines. There was no Plymouth Hemi engine until the 1964 426.

Briggs Cunningham used the Chrysler version in some of his race cars for international motorsports. A Chrysler-powered Cunningham C-5R won its class in 1953. Cunningham switched away from these designs in 1959 when Chrysler temporarily abandoned the hemispherical concept in favor of the wedge-head B engine until 1964. Carl Kiekhaefer also used the Chrysler engines in NASCAR cars owned by him from 1955 and 1956, winning the Grand National Series championship both years.

Collectively, the 1951–1958 Hemi engines are now commonly referred to as first-generation Hemi engines, and the group can be identified by the rear-mounted distributor and the spark plugs in a row down the center of wide valve covers.

1951 Plymouth Hemi V6
There were plans in 1951 for a Plymouth Dual Overhead Cam Hemi V6 displacing  designed by Chrysler's Powerplant Research and Engine Design division. Known internally as A173, it was meant to be a powerful, fuel-efficient alternative to Ford's V8 and to replace Plymouth's venerable flathead six. However, the plans were scrapped because of high build costs and the then-unusual design.

Chrysler and Imperial 
All Chrysler FirePower engines are oversquare; i.e. their bore is larger than their stroke.

331  
This first FirePower engine, used from 1951 to 1955, has a bore of 3.8125(96.8mm) in and a stroke of 3.625(92.1mm) in for a piston displacement of , and a deck height of 10.385"(264mm) ("low deck"). The bore pitch, shared by all Chrysler FirePower engines, was 4.5625"(115.9mm), the largest of any 1st generation Hemi engines. Most used a two-barrel carburetor and produced , with the famous exception of the 1955 Chrysler C-300 equipped with dual Carter WCFB four-barrel carburetors and rated at .

The 331 engine was used in the following applications:
 1951–1955 Chrysler New Yorker
 1951–1954 Chrysler Imperial and 1955 Imperial
 1951 Chrysler Saratoga
 1952 Chrysler Saratoga Club Coupe 
 1952 Chrysler Imperial Parade Phaeton
 1954 Dodge C Series
 1955 Chrysler C-300
 1956 Facel Vega FV2B
 1958 Hongqi CA72
 The Chrysler Air-Raid Siren. At 138 decibels, it is the loudest siren ever made.

354 
The 354, released in 1956, had a bore of 3.9375(100mm) in and stroke of 3.625(92.1mm) in, and the same 10.385"(264mm) low deck height, for an actual displacement of . The 300B engine was rated at , while the New Yorker and Imperial 354 engine configuration produced . For the 300B, an optional  version was available, making it the first American V8 to be rated at one horsepower per cubic inch. (Note that before 1972, horsepower was SAE gross; thereafter, horsepower is SAE net.) The 354 was also modified. The Hemi was optimized for heavy-duty truck service. These were available with one or two four-barrel carburetors, and were offered in Dodge's heaviest-duty models as the 'Power Giant V-8' from 1957 through 1959; they were the largest of four Hemi truck engines offered by Dodge in the 1950s. The 354 was also offered in certain models with polyspheric heads rather than hemi heads. The combustion chambers on these had similarities to both hemi and wedge heads, but were closer in weight to wedge heads. Thus, both 354 poly and 354 Hemi V8 engines were variously available in 1957.

The 354 engine was used in the following applications:
 1956 Chrysler New Yorker
 1956 Chrysler 300B
 1956 Imperial Custom & Crown
 1957 Dodge D-501
 1957–1959 Dodge C Series Pickup

392 
The 392 raised-deck engine released in 1957 had a  bore and  stroke. The actual displacement is . The deck height, at , was  taller than that of the previous blocks. Because its deck was taller, the heads were cast with wider intake ports so that earlier manifolds could be used with the new heads on the new taller block. For 1958, Chrysler offered the 392 in two configurations:  with 9.25:1 compression and  with 10:1 compression, both with a single four-barrel carburetor. A dual four-barrel version of the 392 available in the 1957–58 Chrysler 300C and 300D cars was rated at ; the 300D, and some marine and industrial engines, used a (now rare) adjustable rocker. An extremely rare option available on the 1958 300D was Bendix "Electrojector" fuel injection, with which the 392 was rated at . Due to reliability problems with the primitive onboard computer which controlled the injection system; however, 15 of the 16 300D cars built with the fuel injection option were recalled and retrofitted with carburetors.

The 392 engine was used in the following applications:
 1957–1958 Chrysler New Yorker
 1957–1958 Imperial Custom, Crown, and LeBaron
 1957 Chrysler 300C
 1958 Chrysler 300D
 1958 Facel Vega Excellence (EX)

In the late 1950s and early 1960s, drag racers found the 392 to be a formidable engine and continued to run them competitively into the 1970s. Usual color of the block was silver.

DeSoto 

DeSoto's Hemi engines were called FireDome and served as the naming convention for the DeSoto Firedome sedan.

276 
In 1952, DeSoto introduced its version of the FirePower (FireDome),with a bore of  and stroke of , for a displacement of . The bore pitch, shared by all DeSoto FirePower engines, was . Power output was . It was a hot seller, with 50,000 vehicles using the engine until it was replaced in 1954.

291 
An increase in displacement to  was made for 1955 by increasing the bore to .

330 
The DeSoto engine was enlarged for 1956 to . Bore was the same as the 291 at , but stroke was increased to  and a taller (raised-deck) block was used.

341 
Displacement was increased again for 1956 (DeSoto Adventurer only) and 1957 (Firedome and Fireflite models) to . Bore was now  with stroke remaining at . The DeSoto Adventurer produced  using dual Carter WCFB four-barrel carburetors.
The 1956 DeSoto Adventurer was the premiere named high-performance version—the DeSoto equivalent of the Chrysler 300—using dual Carter WCFB four-barrel carburetors.
The Adventurer engine for 1956 used a displacement of 341 CID (3.78" bore by 3.80" stroke) and had a compression ratio of 9.5:1, using a special hydraulic camshaft profile.

345 
The largest DeSoto engine for 1957 was the DeSoto Adventurer offering  with square bore and stroke dimensions of 3.80 inches. The DeSoto Adventurer used dual Carter WCFB four-barrel carburetors for a rating of , producing one horsepower per cubic inch (the first American car to do so as standard equipment) using a similar intake manifold to the 1956 341 Adventurer and a similar camshaft. The compression ratio remained at 9.5:1.

Dodge 
Dodge's Hemi was introduced in 1953 as the Red Ram. Dodge did not have a V8 engine until one was developed specifically for the line in 1953 based on the 1951 Chrysler hemi design, but downsized for these smaller cars. They have the smallest bore center distance of any hemi engine at . They do not share any major dimensions or components with the larger Chrysler and DeSoto hemi engines, or the Plymouth A engines. From 1955 to 1958 (see 1956 D500 Dodge D-500 cars and packages: early performance cars) lower-performance versions of the Dodge hemi were introduced by substituting less complex poly (single rocker shaft) heads and valve train parts, including one variant only built as a poly (259"). These were used in low-line 1955-58 DeSotos and Dodges, and 1955-56 high-line Plymouths.

Dodge Trucks marketed their version of the Hemi under the name PowerDome.

241 
Dodge introduced the  engine in 1953. Bore was  and stroke was . With a low compression ratio of 7.0:1 (in 1953 and for the 1954 Meadowbrook), the 241 produced . For 1954, the more senior Dodges received  thanks to a higher 7.5:1 compression ratio. This engine is not the same as the Plymouth 241, which had polyspheric, not hemi heads. The 241 only lasted two years, being replaced by the 270 for 1955.

270 
The D553 1955/1956 Dodge Red Ram Hemi 270 displaced  and was used in premium 1955 and 1956 Dodge vehicles. Bore was  and stroke was . It was not the same as the 270 poly-head. In the Dodge Coronet, running 7.6:1 compression ratio, the 270 produced . In higher trims like the Dodge Royal, the "Super Red Ram" ran the same compression ratio but with a four-barrel carburetor produced .

315 
For 1956, Dodge increased the displacement to  with a longer  stroke and a taller raised-deck block and now with a polyspheric heads—no longer a Hemi. But the optional high-performance D-500 version of this engine had a four-barrel carburetor and a larger valved Dodge hemispherical combustion chambered head. Also, a "race only" package called the D-500-1 or DASH 1 was available with a special aluminum dual four-barrel intake that sported a pair of Carter WCFB carburetors similar to the ones on the Chrysler 300B and DeSoto Adventurer. This engine used the same cylinder heads as the base D-500 model.

The D-501 in 57 was the Chrysler 354 engine, not a Dodge-based engine.

325 
Dodge released a  engine for 1957. The "Super Red Ram" engine used a  bore and  stroke. The base engine offering was now a polyspheric chambered head referenced as 'KDS', and a higher performance 325 was offered with hemi heads as the 'KD-500'. Again there was a low volume offering of a 'KD-500-1' with dual four-barrel carburetors. All engines now, however, had hydraulic camshafts even though the hemi headed offerings sported "dimples" in the valve covers for mechanical adjuster clearance.

Second generation: 426 1964–1971

The hemispherical head design was revived in 1964 for a big-block  overhead valve V8, the first engine "Hemi" by Chrysler, a name it had trademarked (and not to be confused with the Chrysler 426 Wedge.  Sometimes retroactively referred to as the "Gen 2" or "2G" Hemi, the 426 Hemi was nicknamed the "elephant engine" at the time, a reference to its high power, heavy weight, and large physical dimensions. Its  deck height and  bore spacing made it the biggest engine in racing at the time.

The 426 Hemi of the 1960s was an engine produced for use in NASCAR, as raced in a Plymouth Belvedere in 1964. It was not initially available to the general buying public. The 426 Hemi was not allowed to compete in NASCAR's 1965 season due to its unavailability in production vehicles sold to the general public and because of complaints by Ford regarding its power. However several special production versions of the Dodge Dart, the Plymouth Fury, and later, in 1965, the Dodge Coronet, were produced with aluminum fenders and bumpers for drag racing and made available to the general public.

Chrysler introduced the "Street Hemi" in 1966 for its intermediate range of cars and sold the required number of Hemi engines to the public to homologate its use for stock car racing in NASCAR events in 1966. The "Street Hemi" was similar to the race Hemi but with dual inline four-barrel Carter AFB carburetors (with automatic choke), lower compression (10.25:1 from 12.5:1) and lower-lift camshaft, with iron exhaust manifolds instead of lighter steel long tube headers.

There were many differences between the Hemi and the 426 Wedge-head, including cross-bolted main bearing caps and a different head bolt pattern.  Although all manufacturers were familiar with multi-valve engines and hemispherical combustion chambers, adding more valves per cylinder and designing the complex valvetrain they require were expensive ways of improving the high–revolutions per minute (rpm) breathing of production vehicles. By canting the angle of the NASCAR-mandated two valves per cylinder, significantly larger valves could be used. The Chrysler 426 Hemi and all Chrysler RBs had oversquare bore and strokes, both the 426 Hemi and 426 Wedge having a bore × stroke of .

The 426 Hemi, in "Street Hemi" form, was produced for consumer automobiles from 1966 through 1971. Hemi-powered Dodge and Plymouth cars produced in the model years of 1966 through 1971 have become collector's items. For example, a 1971 Plymouth Barracuda Convertible equipped with the 426 Hemi engine sold at auction for US$3.5 million in 2014.

The "Street Hemi" version was rated at  at 5000 rpm SAE gross and  at 4000 rpm of torque. In actual dynamometer testing, it produced  and  of torque in purely stock form. Chrysler's sales literature published both the gross  and net  ratings for 1971.

The street version of the second generation Hemi engine was used (optionally, in all but the last case) in the following vehicles:
 1966–1970 Dodge Coronet/Plymouth Belvedere
 1966–1971 Plymouth Satellite
 1966–1971 Dodge Charger
 1966–1971 Jensen FF
 1966–1971 Jensen Interceptor
 1967–1971 Plymouth GTX
 1968 Dodge Dart Super Stock
 1968 Plymouth Barracuda
 1968–1971 Dodge Super Bee
 1968–1971 Plymouth Road Runner
1969 Dodge Charger R/T
 1969 Dodge Charger Daytona
 1970 Plymouth Superbird
 1970–1971 Plymouth Hemi 'Cuda
 1970–1971 Dodge Challenger
 1970 Monteverdi Hai 450

In racing

There were many differences between the racing Hemis and the street version, including but not limited to compression ratio, camshaft, intake manifold, exhaust manifold. Some 1960s NASCAR and NHRA Hemi engines featured magnesium cross-ram intake manifolds and magnesium oil pans in an attempt to reduce the massive weight of the overall engine, along with chain-driven internal dry sump oil systems. Today, aftermarket blocks, heads, intakes, rods, and pistons are usually made of aluminum.

The 426 Hemi also was used in NHRA and AHRA drag racing. Its large casting allowed the engine to be overbored and stroked to displacements unattainable in the other engines of the day.

Third generation: 2003–Present 

The current-production "HEMI" engine heads are flatter and more complex than the 1950s–'70s Hemi V8 chamber. The combustion chambers are no longer truly hemispherical. It uses a coil-on-plug (distributor-less) ignition system and two spark plugs per cylinder to shorten flame travel leading to more consistent combustion and reduced emissions. Like most of Chrysler's past-model Hemi-head engines, the 5.7 version is rated at approximately one horsepower per cubic inch (the current engines are SAE net, whereas the old Hemi engines were rated SAE gross). For the 2009 model year power was increased to 357-395 horsepower (266-291 kW) and 389-410 lb·ft (527-556 N·m)  depending on application. It also achieved 4% better fuel economy. Variable valve timing (VVT) was also introduced.

A new variable displacement technology called Multi-Displacement System (MDS) is used in some versions which can shut off two cylinders on each bank under light load to improve fuel economy.

5.7 

The 5.7 L HEMI was released for model year 2003 on the Dodge Ram pickup trucks to supplant the Magnum 5.9 engine. From 2004 to 2013, it was the only available gasoline engine in the Ram Heavy Duty. Chrysler later made the 5.7 L Hemi available in all models of the 2004 Dodge Ram, Dodge Durango, the 2005 Chrysler 300C, Dodge Magnum R/T, Jeep Grand Cherokee, the 2006 Dodge Charger R/T, Jeep Commander, the 2007 Chrysler Aspen, the 2009 Dodge Challenger R/T, and the 2022 Jeep Wagoneer. For manual transmission applications (Challenger and 3/4- and 1-ton Ram pickups), cylinder deactivation is not included.

The  Hemi in the Ram delivered  and , but  and  for the 300C and Magnum R/T, which is exactly  more than the old 5.9 engine. It is a 90-degree V8, 2-valve pushrod design like the past Magnum series engines, displacing , with a bore of  and a stroke of .

The 5.7 L Hemi is made at Chrysler's Saltillo Engine plant in Ramos Arizpe, Mexico.

The Hemi was on the Ward's 10 Best Engines list for 2003 through 2007, and again in 2009.

This engine has been used in the following vehicles:
 2003–2024 Ram Pickup
 2004–2009, 2011–Present Dodge Durango
 2005–2008 Dodge Magnum R/T
 2005–2023 Chrysler 300C, 
 2010, 2012–2023 Chrysler 300S V8
 2005–2022 Jeep Grand Cherokee
 2006–2023 Dodge Charger R/T
 2006–2010 Jeep Commander
 2007–2009 Chrysler Aspen
 2009–2023 Dodge Challenger R/T
 2022–2023 Jeep Wagoneer

2009 5.7 revisions
Chrysler made various revisions to the 5.7 L for the 2009 model year. The first for all applications was what Chrysler called Variable Camshaft Timing or VCT. VCT (which is essentially variable valve timing) uses an oil control valve that controls oil flow to a unique camshaft sprocket that contains a phasing device, which depending on the operation of the oil control valve, either advances or retards camshaft timing.

Cylinder heads were revised to increase flow. Though the intake manifold was also changed on all applications, it was still model-specific. The Dodge Ram, non-Hybrid Electric Vehicle (HEV) Chrysler Aspens, and non-HEV Dodge Durango utilized an active intake manifold with a short runner valve to optimize torque and horsepower. At lower engine speeds, the valve was closed, resulting in improved low-end torque from the longer runners. At higher engine speeds, the valve was opened, diverting the incoming air into the center of the manifold. The shorter runners resulted in improved horsepower. Passenger cars, Jeep vehicles, as well as HEV Chrysler Aspen and HEV Dodge Durango did not use this manifold; instead, these vehicles utilized a passive intake manifold, which did not have a short runner valve. Also, the new cylinder head came with different spark plug seats: tapered seats were replaced with gasket seats. This change made it impossible to use the old OE Champion RE14MCC4, so the new spark plugs that came with 5.7 HEMI became NGK LZFR5C-11. Besides different seats, the spark plug gap grew from .039" (1.0 mm) to .043" (1.1 mm).

Engines mated to the six-speed manual transmission or used in the Ram Heavy Duty did not feature the Multi-Displacement System (MDS). The new version of the 5.7 L had five different camshaft profiles, all with VCT:
 Active intake without MDS
 Active intake with MDS
 Passive intake without MDS
 Passive intake with MDS
 HEV application (modified version of passive intake with MDS)

Power numbers:
 300C/300S V8: , 
 Charger R/T: , 
 Challenger R/T automatic: , 
 Challenger R/T 6-speed manual: , 
 2009–2012 Ram 1500 truck: , 
 2013+ Ram 1500 truck: , 
 Ram 2500/3500 truck: , 
 Jeep Grand Cherokee and Jeep Commander: , 
 2011+ Dodge Durango: , 
 2009 Chrysler Aspen and Dodge Durango non-HEV: , 
 2009 Chrysler Aspen and Dodge Durango HEV: , 
 2022 Jeep Wagoneer: ,

6.1

The Hemi was also available in a  version that was developed in 2004 for the 2005 Model Year Chrysler 300C SRT8. The engine's bore × stroke was , and many other changes were made to allow it to produce  at 6,200 rpm and  of torque at 4,800 rpm. The engine block differed from the 5.7, with revised coolant channels and oil jets to cool the pistons. A forged crankshaft, lighter pistons, and strengthened connecting rods improved durability. A cast aluminium intake manifold was tuned for high-rpm power and did not include variable-length technology. Chrysler's Multi-Displacement System was not used on the 6.1.

Applications:
 2005–2010 Chrysler 300C SRT-8
 2006–2008 Dodge Magnum SRT-8
 2006–2010 Dodge Charger SRT-8
 2006–2010 Jeep Grand Cherokee SRT-8
 2008–2010 Dodge Challenger SRT-8

6.2 Hellcat
For 2015, Chrysler introduced an all-new high performance supercharged variant of the Hemi engine, called the Hellcat (named after the Grumman F6F Hellcat). It features the same  bore as the 6.4 L Hemi and the same  stroke as the 5.7 L, giving it a total displacement of . The supercharger is a  twin-screw IHI unit with integrated charge coolers, capable of producing  of boost. This engine is rated at  at 6,000 rpm and  at 4,000 rpm of torque and has a compression ratio of 9.5:1. This engine was the most powerful engine produced by Chrysler as well as the most powerful production engine ever in a muscle car until the Dodge Demon was introduced. This engine is not equipped with Chrysler's Multi-Displacement System. In 2017, Mopar announced that it would sell it as a crate engine under the name Hellcrate. A Redeye version with  debuted in the Dodge Challenger in 2019, followed by the Dodge Charger in 2021.

Applications:
 2015–2023 Dodge Challenger SRT Hellcat/Hellcat Redeye
 2015–2023 Dodge Charger SRT Hellcat/Hellcat Redeye
 2018–2021 Jeep Grand Cherokee Trackhawk
 2021 and 2023–present Dodge Durango SRT Hellcat
 2016 Ram 1500 Rebel TRX Concept
 2021–2024 Ram 1500 TRX

6.2 Demon
The Demon version of the Hemi V8 features a number of improvements over the Hellcat variant. It is fitted with a larger, 2.7 L twin-screw supercharger, as well as reinforced reciprocating components, a new camshaft, and several other valvetrain upgrades. With these improvements, the Challenger SRT Demon is rated at 808 horsepower on 91-octane pump gasoline, and 840 horsepower when running on 100-octane unleaded racing gasoline. Cooling is aided by a functional Air-Grabber hood scoop, as well as a unique charge cooling system that makes use of the air-conditioning coolant to lower the intake charge air temperature.

Applications:
 2018 Dodge Challenger SRT Demon

6.4 

Chrysler displayed a larger and more powerful 392-cubic-inch (6.4 L) HEMI in 2005 with a factory-rated output of  and  torque. It is equipped with high-strength forged aluminum alloy pistons. This engine has been available since 2007, as a crate engine under the name 392 HEMI.

The production version of the 392 HEMI was developed in 2010, launched in the 2011 model year Dodge Challenger SRT8 with variable camshaft timing as well as MDS in cars with automatic transmissions. The new 392 HEMI, codenamed "Apache," is based on the third-generation 5.7 L HEMI, codenamed "Eagle," and shares few parts with the 392 crate engine.

Special-edition Chargers and Challengers equipped with this engine, and the engines themselves, featured "392 HEMI" badging in commemorative reference to the first-generation engine of the same displacement. In other applications, the engine is badged as "6.4L HEMI." Output is  and ;

For the 2015 model year, horsepower was increased to  and torque to  in the Charger and Challenger SRT 392 (2015–2018) and R/T Scat Pack (2015–2023) models; the Grand Cherokee SRT only saw a 5 bhp increase. Export models of the Chrysler 300 SRT retained the  and  output.

Applications:

 2023 Chrysler 300C
 2012–2014 Chrysler 300 SRT-8
 2015-2021 Chrysler 300 SRT (Overseas)
 2011–2023 Dodge Challenger SRT-8/SRT 392/Scat Pack
 2012–2023 Dodge Charger SRT-8/SRT 392/Scat Pack
 2018–2024 Dodge Durango SRT
 2012–2021 Jeep Grand Cherokee SRT-8/SRT
 2022–2023 Jeep Grand Wagoneer
 2021–2024 Jeep Wrangler Unlimited Rubicon 392

Ram Heavy Duty truck and chassis-cab version
Starting in model year 2014, the Ram 2500 and 3500 trucks, and Ram 3500, 4500, and 5500 chassis-cabs offered a revised version of the 6.4 L, being re-tuned for better fuel economy and a power band more suitable for hauling and towing than the all-out power of the SRT version. In 2016, it replaced the 5.7 L as the standard gasoline engine in the chassis-cab models.

Power numbers:
 Ram 2500/3500 pickup and 3500 SRW chassis-cab with RFE transmission: , 
 Ram 3500 Mega Cab and 3500 DRW chassis-cab with RFE transmission, 3500 SRW/DRW with Aisin transmission: , 
 Ram 4500 and 5500 chassis-cab: ,

Mopar 426 HEMI (2012–2014)

At the 2012 North American International Auto Show in Detroit, Dodge debuted a Mopar Customized Dodge Charger "Redline" that featured a modern  HEMI V8 engine rated at .

Mopar 426 HEMI 'Hellephant' (2018–2024)
The Hellephant name is a spin on the nickname of the original  HEMI, Elephant, and the modern Supercharged 6.2-liter Hellcat HEMIs. It is a crate engine, supercharged as standard, producing  and  of torque.

Marketing
From February to April 2005, DaimlerChrysler hosted a "What Can You HEMI?" contest promoting alternative uses of the HEMI engines. The top five finalists include HEMI Snowblower, HEMI-Go-Round carousel, "HEMI on Ice" ice resurfacer, HEMI-Shredder, and HEMI Big Wheel (i.e., the child's tricycle of the 1970s). The winner was the HEMI Big Wheel, which had a 5.7 L Hemi in the back that was installed backwards; thus, reverse became the only forward gear. Plate steel was the predominant material, while a rolled tube of steel had to be utilized for the front tire as there were no such tires  in diameter that were as narrow as needed for this project.

Notes

References

External links

 How a hemi engine works
 A Body Hemi engine swaps
 New Hemi technical article at AutoSpeed
 Mopar HEMI Gen II page
 Mopar HEMI Gen III page

Hemi
V8 engines