History of the Challenger’s Hemi Engine

The key to understanding a Hemi requires a basic understanding of the way a standard engine works. Spark plugs, valves, the combustion chamber and the pistons are all, or all could be, impacted by the Hemi design.

The word “Hemi” in essence refers to the shape of the cylinder head’s combustion chamber. Rather than being wedge like in design, as they were on the Chrysler Wedge Engines, they are dome shaped, or Hemispherical; the term the word “Hemi” is short for.

The hemispherical combustion chamber allows for the plugs to be relocated, the valves to be larger and the piston configured for higher compression. When all of these factors are stacked together, you’re left with a pretty incredible amount of horsepower capabilities.

Hemis appeared to the public from Chrysler back in the early 50’s. Interestingly enough, the “hemi” marketing scheme wasn’t introduced at the time. Instead, they were referred to as “FirePower” engines.

Seeing as the first Generation of Challengers wasn’t introduced until the 1970 model year, they would be paired with the second generation of Hemi Engines. This is only appropriate; a legendary car must be paired with a legendary engine.

The real breadwinner of the Hemi engine lineup is the 426 Hemi. The FirePower engines, though a notable stepping stone in the Hemi history, are not exactly power plants like the second generation of Hemi.

The combination of the Hemispherical combustion chambers with massive displacement was a recipe for a legend. This engine was commonly referred to as The Elephant on account of its physical size. Not only were these massive 426 cubic inch engines, that’s 7.0 liters, but they took up almost all of the room of the engine compartment.

Dodge, like the motorhead psychopaths they prove to be year after year, released this monster to the public in the mid-1960s. This engine was paired with all of their legendary performers from the era.

In the 1970s, after they decided to step into the pony car division with the Challenger, it was only natural they jammed one in their too. That’s right; the small E-body legend was paired with the massive 425 hp, 490 lb-ft Elephant engine (at least that’s what they advertised it to produce).

426 Hemi Power Output (1964-1971)

• 425 hp, 490 lb-ft

Like a match made in heaven, the third-gen Challengers would be paired with third-gen Hemi engines. A lot of things separate the third generation of Hemis from the second. The block, pistons and almost every internal part is largely different. Though, the hemispherical combustion chamber has been carried over. 

The displacement of the second-gen Hemis is considerably smaller than the second. The first engines we seen dropped in the Challenger were the 5.7 and 6.1-liter engines. Despite their smaller size, these engines are no slouches in comparison of power.

The first wave of 5.7 Hemis was capable of producing 370 horsepower and 398 lb-ft of torque. The 6.1, which was paired with earlier SRT8 Challengers, came out swinging a slightly larger stick. These engines were capable of producing a similar 425 horsepower to the 426s, on paper, and a whopping 420 lb-ft of torque.

After their initial run in the Challengers from 2008-2010, the 5.7 was taken back and revised. After a few tweaks, the engine produces 375 horsepower and 410 lb-ft of torque. The 6.1 was also replaced around the same time. Dodge introduced the 6.4 liter 392 Hemi.

This engine was much more powerful and from 2010-2014 it produced 470 horsepower and 470 lb-ft of torque. In 2015 it too would be revised, like the 5.7 was earlier, and would produce 485 horsepower and 475 lb-ft of torque. Though, growing in power year after year, the 5.7 and 392 were quickly overshadowed by the most powerful Hemi engines ever produced.

Gen 3 Hemi Power Output

• 5.7L (2008-2010) 370hp & 398lb-ft
• 5.7L (2011-current) 375hp & 410lb-ft
• 6.1L (2008-2010) 425hp & 420lb-ft
• 6.4L (2011-2014) 470hp & 470lb-ft
• 6.4L (2015-current) 485hp & 475lb-ft

We gave credit to the 426 Hemi as the breadwinner of the bunch. This is because it was the engine to put Hemi engines on the map. They were proven to be major contenders in the way of performance by The Elephant. Though the biggest to ever be fitted to a Challenger, they weren’t the most powerful.

Third Gen Challengers shook the world when the Hellcat was released. This engine is slightly smaller than the 392 but packs way more of a punch. With differences in both bore and stroke, the most notable change is the addition of a roots supercharger on top.

Blowers are known to make power but the 6.2 Liter Hemi Hellcat produces a whopping 707 horsepower and 650 lb-ft of torque. Dodge was proudly able to market this as trim level as the most powerful muscle car ever produced.

Despite the already ridiculous power of the Hellcat, Dodge naturally upped the ante. As top dog of the market, Dodge took the same 6.2 liters of Hemi displacement and reworked it. For one year, and one year only, the Demon was made available. This much more powerful engine produces 840 horsepower and 770 lb-ft of torque. This is more than enough power to send a factory Challenger down the quarter mile in 9 seconds.

Hellcat Hemi Power Output

• 6.2L (2015-current) 707hp & 650lb-ft

Demon Hemi Power Output

• 6.2L 840hp & 770lb-ft

The Challenger and the Hemi have always been two names that come to mind when people hear the word “Mopar.” We all know that rumors of the Challenger being revised for 2020 are out there. While we are uncertain of what that means, we know one thing for sure - the Hemi will live on with it.