Editing Chrysler Hemi engine

{{Short description|Series of I6 and V8 engines built by Chrysler}}
{{For|an overview of Hemi engines in general|Hemispherical combustion chamber}}
{{Multiple issues|
{{More citations needed|date=June 2010}}
{{Original research|article|date=December 2008}}
}}
{{Use mdy dates|date=April 2021}}
[[File:Hemi in 300C.jpg|thumb|250px|Early Hemi in a 1957 [[Chrysler 300 letter series|Chrysler 300C]] ]]
[[File:Marine Hemi.JPG|thumb|The Chrysler Marine Hemis were popular in wooden boats such as the [[Chris-Craft Boats|Chris-Craft]] during the 1950s and 1960s]]

The '''Chrysler Hemi engine''', known by the trademark '''Hemi''' or '''HEMI''', refers to a series of high-performance American [[overhead valve]] [[V8 engine]]s built by [[Chrysler]] with [[hemispherical combustion chamber]]s. Three generations have been produced: the FirePower series (with displacements from {{convert|241|cuin|L|1|abbr=on}} to {{convert|392|cuin|L|1|abbr=on}}) from 1951 to 1958;<ref>{{cite web |url= http://www.oldcarbrochures.com/static/NA/Chrysler_and_Imperial/1951_Chrysler/1951_Chrysler_FirePower_Advantages/1951%20Chrysler%20FirePower%20Advantages-01.html |title=1951 Chrysler FirePower Advantages |publisher=oldcarbrochures.com |access-date=January 16, 2014}}</ref> a famed {{convert|426|cuin|L|1|abbr=on}} race and street engine from 1964-1971; and family of advanced Hemis (displacing between {{convert|5.7|L|cuin|0|abbr=on}} {{convert|6.4|L|cuin|0|abbr=on}}  from 2003 to 2024.

The hellcats are used a lot by black people who do drive by in this while sipping lean and eating KFC 
[[Indianapolis Foundry]].{{which|date=May 2024}}{{when|date=May 2024}}{{cn|date=May 2024}}

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

==Design==
{{main|Hemispherical combustion chamber}}

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, {{clarification needed span|text=minimal heat loss to the [[cylinder head]],|reason=How, and why?  A hemisphere has the largest possible area (of any combustion chamber shape of a given diameter); why doesn't it transfer (i.e. lose) more heat than any other smaller shape?  In layman's terms, with a reliable citation, please.|date=May 2024}} and room for two large [[poppet valve|valves]]. However, it allows no more than two valves per cylinder,{{why|date=May 2024}} 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 "[[Crossflow cylinder head|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 (piston engine)|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.<ref name="Allpar">{{cite web |title=Origin of the Mopar Hemi engine, Ardun Heads, and Riley cars |url=https://www.allpar.com/threads/origin-of-the-mopar-hemi-engine-ardun-heads-and-riley-cars.229942/#post-1085224040 |website=Allpar Forums |access-date=March 14, 2022 |date=November 16, 2020}}</ref> 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.<ref name="Allpar"/>

{{anchor|First}}
==First generation: FirePower 1951–1958== <!-- Other articles link here. -->
Chrysler developed its first experimental hemi engine for the [[Republic Aviation Company|Republic]] [[P-47 Thunderbolt]] fighter aircraft. The [[Chrysler IV-2220|XIV-2220]] was an inverted [[V16 engine|V16]] rated at {{convert|2500|hp|kW|-1|abbr=on}}. 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 Motors Company|Continental]] worked together to develop the air-cooled [[Continental AV1790|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 engine|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 {{convert|331|cuin|L|1|abbr=on}} and produced {{convert|180|bhp|kW|1|abbr=on}}. 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_(automobile)#First_generation_(1955–1956):_A_separate_make|Imperial]] called their versions the ''FirePower''. [[DeSoto (automobile)|DeSoto]] called theirs the ''FireDome''. Dodge had a smaller version, known as the ''Red Ram''. Only [[Plymouth (automobile)|Plymouth]] did not have a version, but retained the Dodge [[Polyspheric|poly-head engines]]. There was no Plymouth Hemi engine until the 1964 [[426 Hemi|426]].

[[Briggs Cunningham]] used the Chrysler version in some of his [[race car]]s for international motorsports. A Chrysler-powered [[B. S. Cunningham Company#C-5R|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 [[Chrysler B engine|B engine]] until 1964. [[Carl Kiekhaefer]] also used the Chrysler engines in NASCAR cars owned by him from 1955 and 1956, winning the [[NASCAR Cup Series|Grand National Series]] championship both years.

Collectively, the 1951–1958 Hemi engines are now commonly referred to as first-generation Hemi engines,{{cn|date=March 2023}} and the group can be identified by the rear-mounted [[distributor]] and the [[spark plug]]s in a row down the center of wide valve covers.

===1951 Plymouth Hemi V6===
There were plans in 1951 for a [[Plymouth (automobile)|Plymouth]] [[Overhead camshaft#Double overhead camshaft|Dual Overhead Cam]] Hemi V6 displacing {{convert|235|in3|L|1}} 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 flathead V8 engine|Ford's V8]] and to replace [[Chrysler flathead engine#Straight-6|Plymouth's venerable flathead six]]. However, the plans were scrapped because of high build costs and the then-unusual design.<ref>{{cite web|url=https://www.allpar.com/threads/the-1951-chrysler-3-6-liter-v6-hemi.229888/|title=The 1951 Chrysler 3.6 Liter V6 Hemi|website=Allpar|date=November 16, 2020 }}</ref>

=== Chrysler and Imperial ===
All Chrysler FirePower engines are [[oversquare]]; i.e. their [[Bore (engine)|bore]] is larger than their [[Stroke (engine)|stroke]].<ref name="RedRam"/>

==== 331 ==== <!-- This section is linked from [[Stock car racing]] -->
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 {{convert|331|cuin|L|1|abbr=on}}, 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 {{convert|180|bhp|kW|0|abbr=on}}, with the famous exception of the 1955 [[Chrysler 300 letter series#1955 C-300|Chrysler C-300]] equipped with dual Carter WCFB four-barrel carburetors and rated at {{cvt|300|hp|kW|0}}.<ref>{{cite web |url=https://www.hotrod.com/articles/hrdp-1206-the-early-hemi-guide-of-death/ |title=The Early Hemi Guide of Death |website=Motortrend.com |date=May 21, 2012 |access-date=July 21, 2021 }}</ref><ref>{{cite web |url=http://www.trucktrend.com/how-to/engine/1706-history-of-the-hemi-v-8-engine/ |title=History of the Hemi V-8 Engine |website=Motortrend.com |date=June 5, 2017 |access-date=July 21, 2021 }}</ref>

The 331 engine was used in the following applications:
* 1951–1955 [[Chrysler New Yorker]]
* 1951–1954 [[Chrysler Imperial]] and 1955 [[Imperial (automobile)|Imperial]]{{efn|name=impA|Imperial became a separate make and division unto itself, starting in 1955, and no longer bore the "Chrysler" name.}}
* 1951 [[Chrysler Saratoga]]
* 1952 [[Chrysler Saratoga]] Club Coupe 
* 1952 [[Chrysler Imperial Parade Phaeton]]
* 1954 [[Dodge C series|Dodge C Series]]
* 1955 [[Chrysler 300 letter series#1955 C-300|Chrysler C-300]]
* 1956 [[Facel Vega FV|Facel Vega FV2B]]
* 1958 [[Hongqi CA72]]
* The Chrysler Air-Raid Siren. At 138 [[decibel]]s, it is the loudest siren ever made.<ref>{{cite web|url=https://www.thesirenboard.com/faq.html#Q2|title=Air Raid Sirens FAQ|website=www.thesirenboard.com}}</ref>

==== 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 {{convert|5787|cc|cuin|1|abbr=on}}. The 300B engine was rated at {{convert|340|bhp|kW|0|abbr=on}}, while the New Yorker and Imperial 354 engine configuration produced {{convert|280|bhp|kW|0|abbr=on}}. For the 300B, an optional {{convert|355|hp|kW PS|0|abbr=on}} 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 (automobile)|Imperial Custom & Crown]]{{efn|name=impA}}
* 1957 [[Dodge Coronet|Dodge D-501]]
* 1957–1959 [[Dodge C Series]] Pickup

==== 392 ====
The 392 raised-deck engine released in 1957 had a {{convert|4.00|in|mm|1|abbr=on}} bore and {{convert|3.906|in|mm|2|abbr=on}} stroke. The actual displacement is {{convert|392.67|cuin|cc|0|abbr=on}}. The deck height, at {{convert|10.87|in|mm|1|abbr=on}}, was {{convert|1/2|in|mm|0|abbr=on}} 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: {{convert|325|bhp|kW|0|abbr=on}} with 9.25:1 [[compression ratio|compression]] and {{convert|345|bhp|kW|0|abbr=on}} 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 {{convert|375|bhp|kW|0|abbr=on}}; the 300D, and some marine and industrial engines, used a (now rare) adjustable rocker.<ref name="Hot Rod Magazine online">[http://www.hotrod.com/articles/392-chrysler-hemi-build-dyno-test-whale-motor-respond-bolt-speed-parts/ ''Hot Rod'' Magazine online] (retrieved March 9, 2018)</ref> An extremely rare option available on the 1958 300D was Bendix "Electrojector" [[fuel injection]], with which the 392 was rated at {{convert|390|bhp|kW|0|abbr=on}}. 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.<ref>{{cite book |last=Flory, Jr. |first= J. "Kelly" |title=American Cars, 1946-1959: Every Model, Year by Year |publisher=McFarland |year=2008 |page=899 |isbn=978-0-7864-3229-5 }}</ref>

The 392 engine was used in the following applications:
* 1957–1958 [[Chrysler New Yorker#1957–1959|Chrysler New Yorker]]
* 1957–1958 [[Imperial (automobile)#Second generation (1957–1966)|Imperial Custom, Crown, and LeBaron]]{{efn|name=impA}}
* 1957 [[Chrysler 300 letter series#1957 300C|Chrysler 300C]]
* 1958 [[Chrysler 300 letter series#1958 300D|Chrysler 300D]]
* 1958 [[Facel Vega Excellence]] (EX)

In the late 1950s and early 1960s, [[Drag racing|drag racer]]s found the 392 to be a formidable engine and continued to run them competitively into the 1970s. Usual color of the block was silver.<ref name="Hot Rod Magazine online"/>

=== DeSoto ===
[[File:FiredomeV8,1952.jpg|thumb|New DeSoto Fire Dome engine at 1952 Los Angeles International [[Auto show|Automobile Show]].]]
DeSoto's Hemi engines were called FireDome and served as the naming convention for the [[DeSoto Firedome]] sedan.

==== 276 ====
In 1952, [[DeSoto (automobile)|DeSoto]] introduced its version of the FirePower (FireDome),with a bore of {{convert|3.625|in|mm|2|abbr=on}} and stroke of {{convert|3.344|in|mm|2|abbr=on}}, for a displacement of {{convert|276.1|cuin|L|1|abbr=on}}. The bore pitch, shared by all DeSoto FirePower engines, was {{convert|4.3125|in|mm|2|abbr=on}}.{{cn|date=March 2023}} Power output was {{convert|160|bhp|kW|0|abbr=on}}. It was a hot seller, with 50,000 vehicles using the engine until it was replaced in 1954.

==== 291 ====
An increase in displacement to {{convert|290.8|cuin|L|1|abbr=on}} was made for 1955 by increasing the bore to {{convert|3.72|in|mm|1|abbr=on}}.{{cn|date=March 2023}}

==== 330 ====
The DeSoto engine was enlarged for 1956 to {{convert|329.9|cuin|L|1|abbr=on}}. Bore was the same as the 291 at {{convert|3.72|in|mm|1|abbr=on}}, but stroke was increased to {{convert|3.80|in|mm|1|abbr=on}} and a taller (raised-deck) block was used.{{cn|date=March 2023}}

==== 341 ====
Displacement was increased again for 1956 (DeSoto Adventurer only) and 1957 (Firedome and Fireflite models) to {{convert|341.1|cuin|L|1|abbr=on}}. Bore was now {{convert|3.78|in|mm|1|abbr=on}} with stroke remaining at {{convert|3.80|in|mm|1|abbr=on}}.{{cn|date=March 2023}} The DeSoto Adventurer produced {{convert|320|bhp|kW|0|abbr=on}} 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 {{convert|344.6|cuin|L|1|abbr=on}} with square bore and stroke dimensions of 3.80 inches. The DeSoto Adventurer used dual Carter WCFB four-barrel carburetors for a rating of {{convert|345|bhp|kW|0|abbr=on}}, 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.<ref name="RedRam">{{cite web|url=http://www.thehemi.com/engines.php |title=Hemi Engine Database |publisher=Thehemi.com |access-date=January 16, 2014}}</ref> 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 {{convert|4.1875|in|mm|1|abbr=on}}. 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.<ref>{{YouTube|JZofESfdhQc|DODGE TRUCKS THE POWER GIANTS FOR '58!}}</ref><ref>{{cite web |url=https://clickamericana.com/eras/1950s/new-prestige-styled-58-dodge-power-giants |title=New prestige-styled '58 Dodge Power Giants |website=clickamericana.com |date=October 21, 2013 |access-date=July 21, 2021 }}</ref>

==== {{anchor|241}} 241 ====
Dodge introduced the {{convert|241.3|cuin|L|1|abbr=on}} engine in 1953.<ref name="RedRam" /> Bore was {{convert|3.4375|in|mm|1|abbr=on}} and stroke was {{convert|3.25|in|mm|1|abbr=on}}. With a low compression ratio of 7.0:1 (in 1953 and for the 1954 [[Dodge Meadowbrook|Meadowbrook]]), the 241 produced {{convert|140|bhp|kW|0|abbr=on}}.<ref name="chrysler">{{Cite book | ref = SCC | title = Standard Catalog of Chrysler, 1924-1990 | first = John | last = Lee | publisher = Krause Publications | location = Iola, WI | page = 269 | year = 1990 | isbn = 0-87341-142-0 }}</ref> For 1954, the more senior Dodges received {{convert|150|bhp|kW|0|abbr=on}} thanks to a higher 7.5:1 compression ratio.<ref name=Lee270>[[#SCC|Lee]], p. 270</ref> This engine is not the same as the [[Polyspheric#241|Plymouth 241]], which had polyspheric, not hemi heads. The 241 only lasted two years, being replaced by the 270 for 1955.<ref name=Lee270/>

==== 270 ====
The D553 1955/1956 Dodge Red Ram Hemi 270 displaced {{convert|270|cuin|L|1|abbr=on}} and was used in premium 1955 and 1956 Dodge vehicles. Bore was {{convert|3.625|in|mm|1|abbr=on}} and stroke was {{convert|3.25|in|mm|1|abbr=on}}. It was not the same as the [[Polyspheric#270|270 poly-head]]. In the [[Dodge Coronet]], running 7.6:1 [[compression ratio]], the 270 produced {{convert|183|bhp|kW|0|abbr=on}}. In higher trims like the [[Dodge Royal]], the "Super Red Ram" ran the same compression ratio but with a four-barrel carburetor produced {{convert|193|bhp|kW|0|abbr=on}}.<ref name=Lee271>[[#SCC|Lee]], p. 271</ref>

==== 315 ====
For 1956, Dodge increased the displacement to {{convert|315|cuin|L|1|abbr=on}} with a longer {{convert|3.80|in|mm|1|abbr=on}} 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 {{convert|325|cuin|L|1|abbr=on}} engine for 1957. The "Super Red Ram" engine used a {{convert|3+11/16|in|mm in|sigfig=3|abbr=on}} bore and {{convert|3.80|in|mm|1|abbr=on}} 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.

=={{anchor|Second|426}} Second generation: 426 1964–1971==
{{Infobox automobile engine
| name = 426
| image = 426Hemi1.jpg
| caption = 426 Hemi with dual Carter AFB Carburetors
| manufacturer = [[Chrysler]]
| aka = Elephant engine
| production = 1964–1971
| predecessor = [[Chrysler B engine#426 Wedge|426 Wedge]]
| successor = 
| configuration = [[Naturally aspirated]] [[V8]]
| displacement = {{convert|426|cuin|L|1|abbr=on|lk=on}}
| bore = {{convert|4+1/4|in|mm|1|abbr=on|lk=on}}
| stroke = {{convert|3+3/4|in|mm|1|abbr=on}}
| block = [[Cast iron]]
| head = {{unbulleted list | [[Aluminum]]|Cast iron}}
| valvetrain = [[Overhead valve engine|OHV]] 2 [[Poppet valve|valves]] per [[Cylinder (engine)|cylinder]]
| compression = 10.25:1
| fuelsystem = 2X4 barrel [[Carter Carburetor|Carter AFB]] [[Carburetor]]
| fueltype = [[Petrol engine|Gasoline]]
| oilsystem = {{unbulleted list | [[Wet sump]]|[[Dry sump]]}}
| coolingsystem = [[Radiator (engine cooling)|Liquid-cooled]]
| power = {{unbulleted list | {{convert|425|bhp|kW|0|abbr=on|lk=on}} ([[Horsepower#SAE gross power|Gross]])|{{convert|350|bhp|kW|0|abbr=on}} ([[Horsepower#SAE net power|Net]])}}
| specpower = {{convert|{{#expr:425/6.981 round 1}}|hp|0|abbr=on}} per liter
| torque = {{convert|490|lbft|Nm|0|abbr=on|lk=on}}
| length = 
| width = 
| height = 
| weight = {{convert|843|lb|0|abbr=on|lk=on}}<ref name="specs">{{cite web
|url=http://www.cowtownmopars.com/original/HemiSpecs#specs
|title=Hemi Specifications
|website=Cowtownmopars.com
|access-date=September 8, 2018}}</ref>
}}

The [[hemispherical]] head design was revived in 1964 for a big-block {{convert|426|cuin|L|1|abbr=on}} overhead valve V8, the first engine "Hemi" by Chrysler, a name it had trademarked (and not to be confused with the Chrysler [[Chrysler RB engine#426 Wedge|426 Wedge]].  Sometimes retroactively referred to as the "Gen 2" or "2G" Hemi,<ref>{{cite web|url=http://www.kolossochryslerjeepdodgeramwi.com/2009-mopar-performance-catalog.htm|title=Kolosso Chrysler Dodge Jeep Ram - New Chrysler, Dodge, Jeep, Ram dealership in Appleton, WI 54914|date=March 14, 2016|url-status=dead|archive-url=https://web.archive.org/web/20160314081951/http://www.kolossochryslerjeepdodgeramwi.com/2009-mopar-performance-catalog.htm|archive-date=March 14, 2016}}</ref> the 426 Hemi was nicknamed the "elephant engine" at the time, a reference to its high power, heavy weight, and large physical dimensions.<ref>[https://www.motortrend.com/how-to/what-is-a-hellephant-crate-engine/ "What Is a Hellephant and Why Are They So Rare?"], ''Motor Trend'', Feb 11, 2021|"That's the nickname given to the second-generation Hemi that came out in race-only form in 1964, then in street form in 1966 as the "Street Hemi". It got the name "elephant engine" due to its large size, heavy weight, and prodigious, ground-pounding power."</ref> Its {{convert|10.72|in|mm|1|abbr=on}} deck height and {{convert|4.80|in|mm|1|abbr=on}} 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 [[Fender (vehicle)|fenders]] and [[Bumper (car)|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 [[homologation|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 Carburetor|Carter AFB carburetor]]s{{clarification needed|reason=What did the race 426 have?|date=May 2024}} (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.{{citation needed|date=September 2018}}

There were many differences between the Hemi and the 426 Wedge-head, including [[cross-bolted bearing|cross-bolted main bearing caps]]{{which|Which engine was cross-bolted?|date=May 2024}} and a different head bolt pattern.  Although all manufacturers were familiar with [[multi-valve]] engines and [[hemispherical combustion chamber]]s, adding more valves per [[cylinder (engine)|cylinder]] and designing the complex [[valvetrain]] they require were expensive ways of improving the high–[[revolutions per minute]] (rpm) breathing of [[production vehicle]]s. 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 [[Chrysler RB engine|RB]]s had [[oversquare]] bore and strokes, both the 426 Hemi and [[Chrysler RB engine#426 Wedge|426 Wedge]] having a [[Bore (engine)|bore]] × [[Stroke (engine)|stroke]] of {{convert|4+1/4x3+3/4|in|mm|1|abbr=on}}.

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.<ref>{{cite web|url=https://www.youtube.com/watch?v=W5tQm8HBB2Y| archive-url=https://ghostarchive.org/varchive/youtube/20211028/W5tQm8HBB2Y| archive-date=2021-10-28|title=MECUM SOLD $3.5 Million - 1971 Plymouth Hemi Cuda Convertible|last=Mecum Auctions|date=June 14, 2014|via=YouTube}}{{cbignore}}</ref>

The "Street Hemi" version was rated at {{convert|425|bhp|PS kW|0|abbr=on}} at 5000 rpm [[Horsepower#SAE gross power|SAE gross]] and {{convert|490|lbft|Nm|0|abbr=on}} at 4000 rpm of torque.<ref>{{cite web|url=http://www.automobile-catalog.com/car/1969/635900/dodge_charger_rt_426_v-8_hemi_4-speed_super_track_pack.html|website=automobile-catalog.com|title=1969 Dodge Charger R/T 426 V-8 Hemi 4-speed Super Track Pak|access-date=June 24, 2018}}</ref> In actual [[dynamometer]] testing, it produced {{convert|433.5|hp|kW PS|0|abbr=on}} and {{convert|472|lbft|Nm|abbr=on}} of torque in purely stock form.{{cn|date=March 2023}} Chrysler's sales literature<ref>{{cite web|url= http://www.romocoinc.com/1971-plymouth-rapid-transit-system.htm |archive-url= https://archive.today/20150118064916/http://www.romocoinc.com/1971-plymouth-rapid-transit-system.htm |url-status= dead |archive-date= January 18, 2015 |title=1971 plymouth rapid transit system brochure |publisher=stockmopar.com }}</ref> published both the gross {{convert|425|hp|kW PS|0|abbr=on}} and net {{convert|350|hp|kW PS|0|abbr=on}} ratings for 1971.

[[File:1966 Dodge Charger 426 Hemi engine.JPG|thumb|426 Hemi engine in a 1966 Charger]]

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 (B-body)|Dodge Charger]]
* 1966–1971 [[Jensen FF]]
* 1966–1971 [[Jensen Interceptor]]
* 1967–1971 [[Plymouth GTX]]
* 1968 [[Dodge Dart#Super stock|Dodge Dart Super Stock]]
* 1968 [[Plymouth Barracuda#Second generation (1967–1969)|Plymouth Barracuda]]
* 1968–1971 [[Dodge Super Bee]]
* 1968–1971 [[Plymouth Road Runner]]
*1969 [[Dodge Charger|Dodge Charger R/T]]
* 1969 [[Dodge Charger Daytona]]
* 1970 [[Plymouth Superbird]]
* 1970–1971 [[Plymouth Barracuda#1970|Plymouth Hemi 'Cuda]]
* 1970–1971 [[Dodge Challenger]]
* 1970 [[Monteverdi Hai 450]]

===In racing===
{{expand section|appropriately cited content on the 426 Hemi in drag racing, where it was a dominant force|date=May 2024}}

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 [[Ram-air intake|cross-ram intake manifolds]] and magnesium [[oil pan]]s in an attempt to reduce the massive weight of the overall engine, along with chain-driven internal [[dry sump]] [[Motor oil|oil systems]]. Today, aftermarket blocks, heads, intakes, rods, and [[piston]]s are usually made of aluminum.{{cn|date=May 2024}}

The 426 Hemi also was used in [[NHRA]] and AHRA drag racing. Its large [[casting]] allowed the engine to be overbored and stroked to [[Engine displacement|displacements]] unattainable in the other engines of the day.{{cn|date=May 2024}}

==Third generation: 2003–2024==
{{Infobox automobile engine
| name = Third generation
| image = 2003 5.7 HEMI Magnum Engine (31404717380).jpg
| caption = 2003 5.7 HEMI, the first year of the third generation HEMIs
| manufacturer = [[Chrysler]]
| aka = 
| production = 2003–2024
| predecessor = {{unbulleted list | [[Chrysler LA engine]]|[[Chrysler PowerTech engine]]|[[Chrysler B engine]]}}
| successor = [[Stellantis Hurricane engine]] <small>(for 5.7L and 6.4L versions)</small>
| configuration = 90° [[V8 engine|V8]]
| displacement = {{unbulleted list | {{convert|345|cuin|cc|0|abbr=on|order=flip}}|{{convert|369.7|cuin|cc|0|abbr=on|order=flip}}|{{convert|6166|cc|cuin|abbr=on}}|{{convert|391|cuin|cc|0|abbr=on|order=flip}}}}
| bore = {{unbulleted list | {{convert|3.917|in|mm|2|abbr=on|order=flip}}|{{convert|4.055|in|mm|2|abbr=on|order=flip}}|{{convert|4.090|in|mm|2|abbr=on|order=flip}}}}
| stroke = {{unbulleted list | {{convert|3.578|in|mm|2|abbr=on|order=flip}}|{{convert|3.724|in|mm|2|abbr=on|order=flip}}}}
| block = [[Cast iron]]
| head = [[Aluminum]]
| valvetrain = [[Overhead valve engine|OHV]] 2 valves per cylinder (16 total)
| compression = {{unbulleted list | 9.5:1 | 9.6:1 | 10.3:1 | 10.9:1}}
| fuelsystem = [[Fuel injection|Sequential multiport fuel injection]]
| management = 
| fueltype = [[Gasoline]]
| oilsystem = [[Wet sump]]
| coolingsystem = [[Radiator (engine cooling)|Water-cooled]]
| power = 
| specpower = 
| torque = 
| length = 
| width = 
| weight = 
}}

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 [[Dual ignition|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&nbsp;kW) and 389-410&nbsp;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 ===
[[File:5 7hemi.jpg|thumb|right|5.7 Hemi engine]]
The 5.7 L HEMI was released for model year 2003 on the [[Dodge Ram]] [[pickup truck]]s to supplant the [[Chrysler LA engine#Magnum 5.9|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&nbsp;L Hemi available in all models of the 2004 [[Ram Pickup|Dodge Ram]], [[Dodge Durango]], the 2005 [[Chrysler 300#300C|Chrysler 300C]], [[Dodge Magnum|Dodge Magnum R/T]], [[Jeep Grand Cherokee]], the 2006 [[Dodge Charger|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 {{convert|345|cuin|L|1|abbr=on|order=flip}} Hemi in the Ram delivered {{convert|345|hp|kW|1|abbr=on}} and {{convert|375|lbft|Nm|0|abbr=on}}, but {{convert|340|hp|kW|1|abbr=on}} and {{convert|390|lbft|Nm|0|abbr=on}} for the 300C and Magnum R/T, which is exactly {{convert|100|hp|kW|1|abbr=on}} more than the old 5.9 engine. It is a 90-degree [[V8 engine|V8]], 2-valve [[pushrod]] design like the past Magnum series engines, displacing {{convert|5654|cc|CID|0|abbr=on}}, with a bore of {{convert|3.917|in|mm|2|abbr=on}} and a stroke of {{convert|3.578|in|mm|2|abbr=on}}.<ref>{{cite web |url= http://www.popularhotrodding.com/enginemasters/articles/smallblockshootout/0403phr_chrysler_hemi_57_liter_345ci_engine_review/ |title=Chrysler Hemi 5.7 Liter 345ci - Hello Hemi |date=January 30, 2004 |access-date=April 4, 2014}}</ref>

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, 2011–2024 [[Dodge Durango]]
* 2005–2008 [[Dodge Magnum]] ''R/T''
* 2005–2022 [[Chrysler 300]]C, 
* 2010, 2012–2023 Chrysler 300S V8
* 2005–2022 [[Jeep Grand Cherokee]]
* 2006–2023 [[Dodge Charger (LX)|Dodge Charger]] ''R/T''
* 2006–2010 [[Jeep Commander (XK)|Jeep Commander]]
* 2007–2009 [[Dodge Durango#Chrysler Aspen|Chrysler Aspen]]
* 2009–2023 [[Dodge Challenger]] ''R/T''
* 2022–2023 [[Jeep Wagoneer (WS)|Jeep Wagoneer]]

===2009 5.7 revisions===
Chrysler made various revisions to the 5.7&nbsp;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.<ref>{{Cite web |title=Spark Plug Seat Type |url=https://help.summitracing.com/app/answers/detail/a_id/5076/~/spark-plug-seat-type |access-date=2022-05-12 |website=help.summitracing.com}}</ref> 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&nbsp;mm) to .043" (1.1&nbsp;mm).<ref>{{Cite web |date=2022-05-02 |title=Best Spark Plugs for 5.7 HEMI: How to Choose the Proper Ones |url=https://vinsonar.com/help/best-spark-plugs-for-5-7-hemi/ |access-date=2022-05-12 |website=VIN Sonar {{!}} help - Automotive Guides and Online Tools |language=en-US}}</ref>

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&nbsp;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:{{citation needed|date=November 2020}}
* 300C/300S V8: {{convert|363|hp|kW|0|abbr=on}}, {{convert|394|lbft|Nm|0|abbr=on}}
* Charger R/T: {{convert|370|hp|kW|0|abbr=on}}, {{convert|395|lbft|Nm|0|abbr=on}}
* Challenger R/T automatic: {{convert|372|hp|kW|0|abbr=on}}, {{convert|400|lbft|Nm|0|abbr=on}}
* Challenger R/T 6-speed manual: {{convert|375|hp|kW|0|abbr=on}}, {{convert|410|lbft|Nm|0|abbr=on}}
* 2009–2012 Ram 1500 truck: {{convert|390|hp|kW|0|abbr=on}}, {{convert|407|lbft|Nm|0|abbr=on}}
* 2013+ Ram 1500 truck: {{convert|395|hp|kW|0|abbr=on}}, {{convert|410|lbft|Nm|0|abbr=on}}
* Ram 2500/3500 truck: {{convert|383|hp|kW|0|abbr=on}}, {{convert|400|lbft|Nm|0|abbr=on}}
* Jeep Grand Cherokee and Jeep Commander: {{convert|360|hp|kW|0|abbr=on}}, {{convert|390|lbft|Nm|0|abbr=on}}
* 2011+ Dodge Durango: {{convert|360|hp|kW|0|abbr=on}}, {{convert|390|lbft|Nm|0|abbr=on}}
* 2009 Chrysler Aspen and Dodge Durango non-HEV: {{convert|376|hp|kW|0|abbr=on}}, {{convert|401|lbft|Nm|0|abbr=on}}
* 2009 Chrysler Aspen and Dodge Durango HEV: {{convert|399|hp|kW|0|abbr=on}}, {{convert|390|lbft|Nm|0|abbr=on}}
* 2022 Jeep Wagoneer: {{convert|392|hp|kW|0|abbr=on}}, {{convert|404|lbft|Nm|0|abbr=on}}

===6.1===
[[File:6 1hemi.jpg|thumb|right|6.1 Hemi engine]]
The Hemi was also available in a {{convert|6059|cc|L cuin|1|abbr=on}} version.<ref>{{cite web|url= http://www.media.chrysler.com/dcxms/assets/specs/2007Chrysler300CSRT8FASpecifications.pdf |title=2007 Chrysler 300C SRT8 - Feature Availability |publisher=media.chrysler.com |access-date=January 16, 2014}}</ref> The engine's [[Bore (engine)|bore]] × [[Stroke (engine)|stroke]] was {{cvt|103x90.9|mm|in|3|abbr=on}}, and many other changes were made to allow it to produce {{convert|425|bhp|kW PS|0|abbr=on}} at 6,200&nbsp;rpm and {{convert|420|lbft|Nm|0|abbr=on}} of torque at 4,800&nbsp;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 rod]]s improved durability. A cast aluminium [[intake manifold]] was tuned for high-rpm power and did not include [[variable length intake manifold|variable-length]] technology. [[Chrysler]]'s [[Multi-Displacement System]] was not used on the 6.1.

Applications:
* 2005–2010 [[Chrysler 300]]C ''SRT-8''
* 2006–2008 [[Dodge Magnum]] ''SRT-8''
* 2006–2010 [[Dodge Charger (LX)|Dodge Charger]] ''SRT-8''
* 2006–2010 [[Jeep Grand Cherokee]] ''SRT-8''
* 2008–2010 [[Dodge Challenger]] ''SRT-8''

===6.2 Hellcat{{Anchor|6.2|6.2 L|Hellcat|Turbocharged}}===
For 2015, Chrysler introduced an all-new high performance [[supercharger|supercharged]] variant of the Hemi engine, called the '''Hellcat''' (named after the [[Grumman F6F Hellcat]]).<ref name=enginelabs /> It features the same {{convert|4.09|in|mm|abbr=on|1}} bore as the 6.4&nbsp;L Hemi and the same {{convert|3.578|in|mm|abbr=on|1}} stroke as the 5.7 L, giving it a total displacement of {{convert|6166|cc|L cuin|1|abbr=on}}.<ref name=enginelabs /> The supercharger is a {{convert|2380|cc|cuin|abbr=on}} [[twin-screw supercharger|twin-screw]] [[IHI Corporation|IHI]] unit with integrated [[charge cooler]]s, capable of producing {{convert|11.6|psi|kPa bar|abbr=on}} of boost.<ref name=SAE /> This engine is rated at {{convert|707|hp|PS kW|abbr=on}} at 6,000 rpm and {{convert|650|lbft|Nm|0|abbr=on}} at 4,000 rpm of torque<ref name=enginelabs /> and has a [[compression ratio]] of 9.5:1.<ref name=enginelabs>{{cite web|last1=Magda|first1=Mike|title=SRT Engineer Explains How Hellcat Hemi Pulls 717 Horsepower|url=http://www.enginelabs.com/news/hellcat-hemi-chief-engineer-provides-engine-details/|website=enginelabs.com|date=July 24, 2014 |access-date=November 4, 2014}}</ref> 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.<ref name=SAE /> This engine is not equipped with Chrysler's [[Multi-Displacement System]].<ref name=SAE>{{cite web|title=Chrysler's new Hellcat V8 gets 707-hp SAE rating|url=http://articles.sae.org/13227/|website=SAE International |publisher=[[SAE International|SAE]]|access-date=November 4, 2014}}</ref> In 2017, Mopar announced that it would sell it as a [[crate engine]] under the name Hellcrate.<ref>[http://www.roadandtrack.com/motorsports/a13117952/hellcrate-dodge-hellcat-crate-engine-info-pricing/ You Can Buy a 707-HP Hellcat Crate Engine Directly From Mopar] - Brian Silvestro, Road and Track, October 30, 2017</ref> A Redeye version with {{convert|797|hp|PS kW|abbr=on}} debuted in the Dodge Challenger in 2019, followed by the Dodge Charger in 2021.

Applications:
* 2015–2023 [[Dodge Challenger (2008)|Dodge Challenger SRT Hellcat/Hellcat Redeye]]
* 2015–2023 [[Dodge Charger (LX/LD)|Dodge Charger SRT Hellcat/Hellcat Redeye]]
* 2018–2021 [[Jeep Grand Cherokee (WK2)|Jeep Grand Cherokee Trackhawk]]
* 2021 and 2023–2025 [[Dodge Durango|Dodge Durango SRT Hellcat]]
* 2017 [[Ram Rebel TRX|Ram 1500 Rebel TRX Concept]]
* 2021–2024 [[Ram Pickup (fifth generation)|Ram 1500 TRX]]

===6.2 Demon{{Anchor|6.2|6.2 L|Demon|Supercharged}}===
The Demon version of the Hemi V8 features a number of improvements over the Hellcat variant. It is fitted with a larger, 2.7&nbsp;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|Dodge Challenger SRT Demon]]

=== 6.4 ===
[[File:Dodge Challenger SRT-8 (2011) - 6.4L 392 Hemi V8 Engine - 3.jpg|right|thumb|392 CID V8 HEMI Engine]]
[[File:392 HEMI badge crop.jpg|thumb|392 HEMI badge]]
Chrysler displayed a larger and more powerful 392-cubic-inch (6.4 L)<!--more precisely: 6,424 cc or 391.0 CID--> HEMI in 2005 with a factory-rated output of {{convert|525|hp|kW PS|0|abbr=on}} and {{convert|510|lbft|Nm|0|abbr=on}} 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.<ref name=392chrylsermedia/>

The production version of the 392 HEMI was launched in the 2011 Dodge Challenger SRT8 with variable camshaft timing as well as MDS in cars with automatic transmissions.<ref>{{cite web|url= http://www.thehemi.com/news.php?id=20060228-1 |title=Mopar Performance Parts 6.4L 392ci HEMI Crate Engine |publisher=Thehemi.com |date=February 28, 2006 |access-date=January 16, 2014}}</ref> The new 392 HEMI, codenamed "Apache," is based on the third-generation 5.7&nbsp;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.<ref>{{cite news|url= http://content.usatoday.com/communities/driveon/post/2010/10/dodge-ditches-silly-metric-system-on-challenger-srt8-392/1 |title=Dodge dumps silly metric system on Challenger '392' |first=Chris |last=Woodyard |work=USA Today |date=October 27, 2010 |access-date=January 16, 2014}}</ref><ref>{{cite web |url=http://www.media.chrysler.com/dcxms/assets/specs/2011_Challenger392_Specifications.pdf |title=2011 Dodge Challenger SRT8 392 - Specifications |publisher=media.chrysler.com |access-date=January 16, 2014 |url-status=dead |archive-url=https://web.archive.org/web/20120916011533/http://www.media.chrysler.com/dcxms/assets/specs/2011_Challenger392_Specifications.pdf |archive-date=September 16, 2012}}</ref> In other applications, the engine is badged as "6.4L HEMI."{{citation needed|date=April 2017}} Output is {{convert|470|hp|kW|0|abbr=on}} and {{convert|470|lbft|Nm|0|abbr=on}};<ref name=392chrylsermedia>{{cite web |url=http://media.chrysler.com/newsrelease.do?id=10182&mid=261 |title=2011 Dodge Challenger SRT8 392 Debuts with Newest HEMI V-8 |publisher=Chrysler LLC |date=November 15, 2010 |access-date=April 24, 2011}}</ref>

For the 2015 model year, horsepower was increased to {{convert|485|hp|kW|0|abbr=on}} and torque to {{convert|475|lbft|Nm|0|abbr=on}} 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&nbsp;bhp increase. Export models of the Chrysler 300 SRT retained the {{convert|470|hp|kW|0|abbr=on}} and {{convert|470|lbft|Nm|0|abbr=on}} output.{{citation needed|date=July 2021}}

Applications:

* 2023 [[Chrysler 300|Chrysler 300C]]
* 2012–2014 [[Chrysler 300|Chrysler 300 SRT-8]]
* 2011–2023 [[Dodge Challenger#Third generation (2008–2023)|Dodge Challenger SRT-8/SRT 392/Scat Pack]]
* 2012–2023 [[Dodge Charger (LX/LD)#Charger SRT 392|Dodge Charger SRT-8/SRT 392/Scat Pack]]
* 2018–2025 [[Dodge Durango#Third generation (WD; 2011)|Dodge Durango SRT]]
* 2012–2021 [[Jeep Grand Cherokee (WK2)|Jeep Grand Cherokee SRT-8/SRT]]
* 2022–2023 [[Jeep Wagoneer (WS)|Jeep Grand Wagoneer]]
* 2021–2025 [[Jeep Wrangler (JL)|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&nbsp;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&nbsp;L as the standard gasoline engine in the chassis-cab models.

Power numbers:{{citation needed|date=November 2020}}
* Ram 2500/3500 pickup and 3500 SRW chassis-cab with RFE transmission: {{convert|410|hp|kW|0|abbr=on}}, {{convert|429|lbft|Nm|0|abbr=on}}
* Ram 3500 Mega Cab and 3500 DRW chassis-cab with RFE transmission, 3500 SRW/DRW with Aisin transmission: {{convert|370|hp|kW|0|abbr=on}}, {{convert|429|lbft|Nm|0|abbr=on}}
* Ram 4500 and 5500 chassis-cab: {{convert|366|hp|kW|0|abbr=on}}, {{convert|429|lbft|Nm|0|abbr=on}}

===Mopar 426 HEMI (2012–2014)===
[[File:426 HEMI in a 2013 Dodge Charger.jpg|thumb|The 426 HEMI in a Dodge Charger Redline]]
At the 2012 North American International Auto Show in Detroit, Dodge debuted a Mopar Customized Dodge Charger "Redline" that featured a modern {{convert|426|CID|L|1|adj=on}} HEMI V8 engine rated at {{cvt|590|hp|kW PS|0}}.<ref>{{cite web|url=http://www.media.chrysler.com/newsrelease.do?id=11852&mid=6|title=FCA US Media - Mopar Introduces Dodge Charger Redline Infused With New High Output 426 HEMI Aluminum Crate Engine and More Aggressive Style}}</ref><ref>{{cite web|url= http://jalopnik.com/5883351/dodge-charger-redline-426-live-photos/ |title=Dodge Charger Redline 426: Live Photos |first=Matt |last=Hardigree |publisher=Jalopnik |date=February 8, 2012 |access-date=January 16, 2014}}</ref>

===Mopar 426 HEMI 'Hellephant' (2018–2024)===
The Hellephant name is a spin on the nickname of the original {{convert|426|CID|L|1|adj=on}} HEMI, Elephant, and the modern Supercharged 6.2-liter Hellcat HEMIs. It is a crate engine, supercharged as standard, producing {{cvt|1000|hp|kW|0}} and {{cvt|950|lbft|Nm|0}} 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 (tricycle)|Big Wheel]] (i.e., the child's tricycle of the 1970s).<ref>{{cite web|first=Alannah |last=Tremblay |url=http://www.automobile.com/daimlerchrysler-announces-winner-of-zany-what-can-you-hemi-contest.html |title=New & Used Cars Auto Parts Auto Insurance Auto Loans DaimlerChrysler Announces Winner of Zany "What Can You HEMI?" Contest! |website=Automobile.com |access-date=November 7, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20110707191357/http://www.automobile.com/daimlerchrysler-announces-winner-of-zany-what-can-you-hemi-contest.html |archive-date=July 7, 2011 }}</ref><ref>{{cite web|last=Kaehler |first=Justin |url= http://cars.ign.com/articles/628/628210p1.html |title=That thing got a HEMI? |publisher=Cars.ign.com |date=June 22, 2005 |access-date=January 16, 2014}}</ref><ref>{{cite press release|url= http://www.prnewswire.com/news-releases/five-finalists-named-in-what-can-you-hemir-contest-54427132.html |title=Five Finalists Named in 'What Can You HEMI(R)?' Contest |publisher=PR Newswire |date=May 16, 2005 |access-date=January 16, 2014}}</ref> The winner was the HEMI Big Wheel, which had a 5.7&nbsp;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 {{convert|4|ft|cm|0|adj=on}} in diameter that were as narrow as needed for this project.<ref>{{cite web| last=Keegan | first=Walter J. Jr. |url= http://www.autoblog.com/2005/06/18/what-can-you-hemi-contest-winner/ |title="What can you Hemi?" contest winner |publisher=Autoblog.com |date=December 18, 2005 |access-date=January 16, 2014}}</ref>

==Notes==
{{Notelist}}

==References==
{{Reflist|30em}}

==External links==
{{commons category|Chrysler Hemi engines}}
* [http://auto.howstuffworks.com/hemi.htm How a hemi engine works]
* [http://www.forabodiesonly.com/mopar/forums/new-hemi-engine-swaps.83/ A Body Hemi engine swaps]
* [https://web.archive.org/web/20081121202132/http://www.autospeed.com/cms/A_2060/article.html New Hemi technical article at AutoSpeed]
* [https://web.archive.org/web/20111220134637/http://www.mopar.com/assets/pdf/performance/catalog/Hemi_Gen_II.pdf Mopar HEMI Gen II page]
* [https://web.archive.org/web/20111220124821/http://www.mopar.com/assets/pdf/performance/catalog/Hemi_Gen_III.pdf Mopar HEMI Gen III page]

{{DEFAULTSORT:Chrysler Hemi Engine}}
[[Category:Chrysler engines|Hemi]]
[[Category:V8 engines]]