The 2005 – 2023 Hemi powerplant can be seen as one of the most successful engines, being in continuous production for 18 years.
Here it is in cutaway in original non-Chrysler 300 dress courtesy of David Kimble.

The 2005-2023 Chrysler Hemi

The 2005-2023 Chrysler Hemi  was introduced as a replacement V-8 for the Corporation’s performance products. That it has stayed in production for almost 20 years speaks to the great design and ability to be enhanced – all the way up to over 1,000 horsepower.

The Gen 3 “HEMI” engine heads are flatter and more complex than the Gen 1 1950s and the Gen 2 1964-72 Hemi V8 chambers that were true hemispherical. The new engine’s 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  for more consistent combustion and reduced emissions. The original 5.7 version is rated at approximately one horsepower per cubic inch SAE net, whereas the old Hemi engines were rated SAE gross.

Modifications for the 2009 model year increased power to 357-395 horsepower and torque to 389-410 lb·ft depending on application. Variable valve timing (VVT) was also introduced. Further, a variable displacement technology called Multi-Displacement System (MDS) is used in some versions. It can shut off two cylinders on each bank under light load to improve fuel economy.

The 5.7L Hemi Engine

Here is the original 5.7L Hemi in Chrysler 300 dress.

The Gen 3 5.7 L L (345 CID) Hemi was released for model year 2003 on the Dodge Ram pickup trucks. Chrysler later made the 5.7 L Hemi available in 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 cylinder deactivation was not included.

The 5.7 in the Ram delivered 345 HP and 375 lb⋅ft of torque, and 340 HP and 390 lb⋅ft of torque for the 300C and Magnum R/T – 100 hp more than the old 5.9 OHV V-8 engine. It is a 90-degree V8, 2-valve pushrod design like the past Magnum series engines, displacing 5,654 cc (345 CID), with a bore of 3.917″ and a stroke of 3.578″.

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

The 5.7L engine is used in the following vehicles:

• • 2003–present Ram Pickup
  • 2004–2009, 2011–Present Dodge Durango
  • 2005–2008 Dodge Magnum R/T
  • 2005–present Chrysler 300C, 300S V8 (2010, 2012–Present)
  • 2005–present Jeep Grand Cherokee
  • 2006–present Dodge Charger R/T
  • 2006–2010 Jeep Commander
  • 2007–2009 Chrysler Aspen
  • 2009–present Dodge Challenger R/T
  • 2022–present Jeep Wagoneer

2009 5.7L Revisions

Chrysler made revisions to the 5.7 L for the 2009 model year. The first was Variable Camshaft Timing or VCT. VCT uses an oil control valve that manages oil flow to a camshaft sprocket that contains a phasing device, which either advances or retards camshaft timing.

The second was that the cylinder heads were revised to increase flow. The new cylinder head came with different spark plugs seats: tapered seats were replaced with gasket seats – the new spark plugs are NGK LZFR5C-11. Besides different seats, new spark plugs got increased gap from 0.039″ to 0.043″.

Third, the intake manifold was changed on all applications, but those changes were model specific.

• • Dodge Ram, non-Hybrid Electric Vehicle (HEV) Chrysler Aspens, and non-HEV Dodge Durango utilize an active intake manifold with a short runner valve to optimize torque and horsepower. At lower engine RPM the valve is closed, resulting in improved low-end torque from the longer runners. At higher engine RPM the valve is opened, diverting the incoming air into the center of the manifold. The shorter runners result in improved horsepower.
  • Passenger cars, Jeep vehicles, as well as HEV Chrysler Aspen and HEV Dodge Durango do not use this manifold; instead, these vehicles utilize a passive intake manifold, which does not have a short runner valve.

This new version of the 5.7 L has five different camshaft profiles. All have VCT.

• • Active intake with MDS
  • Active intake without MDS
  • Passive intake with MDS
  • Passive intake without MDS
  • HEV Application (modified version of passive intake with MDS)

Power numbers also changed:

• • 300C/300S V8: 363 HP and 394 lb⋅ft of torque
  • Charger R/T: 370 HP and, 395 lb⋅ft of torque
  • Challenger R/T Automatic: 372 Hp and 400 lb⋅ft of torque
  • Challenger R/T 6 Speed Manual: 375 HP and 410 lb⋅ft of torque
  • 2009-2012 Ram 1500 Truck: 390 HP and 407 lb⋅ft of torque
  • 2013-Present Ram 1500 Truck: 395 HP and 410 lb⋅ft of torque
  • Ram 2500/3500 Truck: 383 HP and 400 lb⋅ft of torque
  • Jeep Grand Cherokee and Jeep Commander: 360 HP and 390 lb⋅ft of torque
  • 2011-Present Dodge Durango: 360 HP and 390 lb⋅ft of torque
  • 2009 Chrysler Aspen and Dodge Durango non-HEV: 376 HP and 401 lb⋅ft of torque
  • 2009 Chrysler Aspen and Dodge Durango HEV: 399 HP and 390 lb⋅ft of torque
  • 2022 Jeep Wagoneer: 392 HP and 404 lb⋅ft of torque

The 6.1L Hemi engine

The Hemi is also available in a 6.1 L, 369.7 CID version. This engine’s bore x stroke is 4.055 in × 3.579 in. It produces 425 HP at 6,200 RPM and 420 lb⋅ft of torque at 4,800 RPM. The engine block is different from the 5.7, with revised coolant channels and oil jets to cool the pistons. A forged crankshaft, lighter pistons and strengthened connecting rods were added for durability. A cast aluminium intake manifold is tuned for high-rpm power and does not include variable-length technology. Chrysler’s Multi-Displacement System is 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

The 6.2L “Hellcat” engine

Various versions of the supercharged Hemi exist. The most common being the “Hellcat”

For 2015, Chrysler introduced an all-new high performance supercharged variant of the Hemi engine, called “Hellcat”. It has a 4.09 in bore and the same 3.578 in stroke as the 5.7 L, giving it a total displacement of 6.2 L, 376.3 CID. The supercharger is a 2,380 cc (145 CID) twin-screw IHI unit with integrated charge coolers, capable of producing 11.6 psi of boost. It is rated at 707 HP at 6,000 RPM and 650 lb⋅ft of torque 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 until the Dodge Demon was introduced. This engine is not equipped with Chrysler’s Multi-Displacement System. Since 2017, it is sold as a crate engine under the name “Hellcrate”. A “Redeye” version with 797 HP debuted in the Dodge Challenger in 2019, followed by the Dodge Charger in 2021.

Applications:

• • 2015–Present Dodge Challenger SRT Hellcat
  • 2015–Present Dodge Charger SRT Hellcat
  • 2018–2021 Jeep Grand Cherokee Trackhawk
  • 2021 Dodge Durango SRT Hellcat
  • 2017 Ram 1500 Rebel TRX Concept
  • 2021–Present Ram 1500 TRX

6.2L “Demon” engine

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, and also has reinforced reciprocating components. A new camshaft, and several other valvetrain upgrades are also included. With these improvements, the Challenger SRT Demon is rated at 808 HP on 91-octane pump gasoline, and 840 HP utilizing 100-octane 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 L 392 CID V8 HEMI Engine

6.4L “392” Hemi engine

The “392” version of the Hemi was a 6.4L version that added even more HP

Chrysler displayed a larger and more powerful 392 CID (6.4 L) HEMI in 2005 with a factory-rated output of 525 HP and 510 lb⋅ft of torque. It is equipped with high-strength forged aluminum alloy pistons. This engine has been available since 2007 as a crate engine as “392 HEMI”.

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. The 392 HEMI is code named “Apache”, and is based on the third-generation 5.7 L HEMI, (code named “Eagle”) and shares few parts with the 392 crate engine.

Special-Edition Chargers and Challengers equipped with this engine, and the engines themselves, bear “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 470 HP and 470 lb⋅ft of torque.

For the 2015 model year, horsepower was increased to 485 HP and torque to 475 lb⋅ft in the Charger and Challenger SRT 392 (available 2015-2018) and R/T Scat Pack (available 2015–present). as well as the Grand Cherokee SRT. Export models of the Chrysler 300 SRT had 470 HP and 470 lb⋅ft of torque.

Applications:

• • Chrysler 300 SRT
  • Dodge Challenger SRT 392
  • Dodge Charger SRT 392
  • Dodge Durango SRT
  • Jeep Grand Cherokee SRT
  • Jeep Grand Wagoneer
  • Jeep Wrangler Unlimited Rubicon 392

Heavy Duty Truck and Cab Chassis Hemi

Starting in model year 2014, the Ram 2500 and 3500 trucks, and Ram 3500, 4500, and 5500 Cab Chassis 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 gas engine in the Cab Chassis models.

Power

• • 2500 and 3500 Pickup, 3500 SRW Cab Chassis with RFE transmission: 410 HP and 429 lb⋅ft of torque.
  • 3500 Mega Cab, 3500 DRW Cab Chassis with RFE transmission, 3500 SRW/DRW with Aisin Transmission: 370 HP and 429 lb⋅ft of torque.
  • 4500 and 5500 Cab Chassis: 366 hp (273 kW), 429 lb⋅ft (582 N⋅m)

426 CID HEMI engine

At the 2012 North American International Auto Show in Detroit, Dodge debuted a Mopar Customized Dodge Charger “Redline” that featured a modern 426 CID (7.0 L) HEMI V8 engine rated at 590 HP. When issued it was called the “Hellephant” (2018-present)

The Hellephant name is a spin on the nickname of the original 426 cubic inch HEMI, called “Elephant”, merged with the modern Supercharged 6.2L “Hellcat” HEMIs. It is a crate engine, supercharged as standard, producing 1,000 HP and 950 lb.-ft of torque.