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The 6.4-liter HEMI (392) engine was first introduced back in 2011. In its first iteration, this engine delivered 470 horsepower and 470 lb-ft of torque, and it quickly gained popularity among muscle-car enthusiasts and performance SUV and truck buyers. The second iteration of the 6.4 was introduced in 2015, and thanks to a new intake manifold and some tuning, power was increased to 485 horsepower and 475 lb-ft of torque.

Overall, the 6.4-liter HEMI engine can be found under the hood of vehicles like the Dodge Challenger and Charger, the Chrysler 300, the Jeep Grand Cherokee and Wrangler Rubicon 392, and Ram heavy-duty pickup trucks. The 6.4 is characterized by its naturally-aspirated architecture, a forged steel crankshaft, hypereutectic pistons with oil squirters, cross-bolted main caps, and aluminum twin-spark cylinder heads with large valves.

In its top-spec production form, the 6.4-liter (392) HEMI delivers 485 horsepower and 475 lb-ft of torque. While MotorTrend outlines ten different steps for building a 1,000-horsepower 6.4-liter HEMI, if you’re not a fan of wrenching and want big power straight out of the box, here are five engines more powerful than the 6.4-liter HEMI.

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Chevy’s 2019 5.2-liter supercharged V8, also known as the LT5, is one of GM’s most powerful supercharged small-block engines. This engine is found in the C7-generation Corvette ZR1 and is rated at 755 horsepower and 715 lb‑ft of torque. Compared with the 6.4-liter HEMI, the LT5 is approximately 56% more powerful from the factory.

The main reason it outclasses the 6.4 is the supercharger. Besides the 1,000+ horsepower LT6 and LT7, the LT5 is one of the most powerful engines ever put in a Corvette. Moreover, the 6.2-liter LT5 was the last “true” muscle-car V8, as all later 5.5-liter Corvette engines in the C8 generation were flat-plane crank V8s that offered a markedly different driving experience.

The LT5 also employs dual-fuel injection, dry‑sump lubrication, an upgraded high-strength steel crankshaft, and a redline of 6,500 RPM. The differences between the 6.4-liter HEMI and the LT5 largely reflect the engines’ primary purposes. Where the LT5 was designed for a track-focused, top-spec performance car, the 6.4-liter is designed for muscle cars, SUVs, trucks, and even luxury Cadillacs.

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The Ford 5.2-liter Predator V8 was introduced for the 2020 Ford Mustang Shelby GT500, and is also one of the most powerful V8 engines Ford ever made. Besides the GT500, the “Predator” was also found for the late 14th-generation V8 Ford F-150 Raptor. Such a massive power output is due to the 2.65-liter Eaton TVS supercharger, a robust aluminum block, and forged internals. Combined, the “Predator” is good for 760 hp at 7,300 rpm and 625 lb‑ft of torque.

This makes it approximately 56% more powerful than the 6.4-liter engine, even though it has a much smaller displacement. We listed the “Predator” on our list of the greatest Ford V8 engines ever made because it uses a cross-plane-crank V8 architecture that still sounds like a muscle car, has a 7,500 RPM redline, and is used in a car that can do both straight-line speed and high-speed cornering. 

It is a high-revving, aggressive engine designed for performance and speed. The 6.4-liter HEMI is not nearly as aggressive in most of its applications. All in all, the “Predator” is what Ford Mustang enthusiasts wanted all along because the 5-liter naturally-aspirated Coyote never went over 500 horsepower from the factory. To make it happen, you needed a supercharger.

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The Dodge 6.2-liter supercharged Hellcat V8 is the “next step up” from the 392 6.4-liter HEMI. Where the 6.4 is used for muscle cars, SUVs, and daily drivers, the 6.2-liter Hellcat is a certified high-end performance car engine used in the Dodge Challenger Hellcat Demon 170, the Hennessy H1000 Hellcat Last Stand, the Dodge Demon, the Dodge Durango SRT Hellcat, and the Ram 1500 TRX — all among the coolest Hellcat-powered cars. 

Thanks to a base output of 707 horsepower and 650 lb-ft of torque, even the “entry-level” Hellcat is 46% more powerful than the 6.4-liter naturally aspirated 392. In its top-end (standard) variant found in the Hellcat Redeye, the 6.2-liter pushes out 797 horsepower and 707 lb-ft of torque (99% more powerful than the 6.4-liter 392. This power increase is primarily due to a larger 2.7-liter supercharger, compared with the 2.4-liter in the “standard” 6.2.

With reinforced internals (pistons, rods, crank, main caps), upgraded “SRT Power Chiller” cooling, and an even more massive three-liter supercharger, the Demon 170’s 6.2-liter Hellcat dials that number up to a staggering 1,025 horsepower and 945 lb-ft of torque (on E85). This is a 111% increase over the 6.2-liter 392 and the most powerful factory Hellcat ever.

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All of the engines we mentioned here are supercharged, while the 6.4-liter is naturally aspirated. However, if you want a naturally-aspirated engine that still pushes out more than the 6.4-liter, the massive 7-liter LS7 V8 by Chevy is exactly that. This engine was introduced in 2006 for the C6 Corvette ZO6, and delivers 505 horsepower with 481 lb-ft of torque, about 5% more powerful than the 6.4-liter. 

The LS7 is a hand-built engine. It uses an iron forged cylinder block, titanium connecting rods, aluminum race-bred cylinder heads, and a dry-sump oiling system.  All of it is designed for extreme high-revving reliability. Its high-lift camshaft and performance-tuned intake and exhaust allow the engine to rev to a 7,000 RPM redline. 

The LS7 is widely regarded as one of the best engines ever made because of its availability, impressive engineering, and the fact that it was offered as a 570-horsepower/540 lb-ft crate engine all the way up to 2022 – 17% more powerful than the 6.4 392 HEMI. The Clunie Garage YouTube channel even called it “GM’s greatest ever” because of its flexibility and power. 

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One of the craziest engines Dodge ever made was the 8.4-liter V10 found in a late-model Dodge Viper. This engine is capable of pushing out 645 horsepower and 600 lb-ft of torque, all while also being a naturally aspirated engine — bigger than the engine found in a Bugatti. That is approximately 33% more powerful than the 6.4-liter, largely thanks to its larger size and displacement. 

This V10’s output also relies on a forged steel crankshaft, an aluminum block, and high-lift camshafts. Its massive displacement and long-stroke design give it a distinctively muscular sound and immense low-end torque, making it one of the most visceral naturally aspirated engines you can get. What makes the Dodge Viper V10 engine so special is that it was a purpose-built engine – lightweight, visceral, and purely mechanical. 

Although it has a relatively low 6,200 RPM redline, this makes the 8.4-liter big on torque, something many other naturally aspirated V10s lack because they often prioritize higher redlines. The Dodge Viper was discontinued in 2017, and with it, this incredible engine came to an end.