Dodge 6.4 vs 5.7 HEMI Specs, Performance, Reliability, MPG
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Dodge 6.4 HEMI vs 5.7 HEMI

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Zach is a founder of 8020 Media and TuningPro. He’s been repairing, upgrading, tuning, and writing about cars & engines for over a decade. Zach has written over 400 automotive articles and continues to be a lead writer for TuningPro. His passion, experience, and deep technical knowledge make him a go-to resource for readers looking to take their car to the next level.

The Dodge/RAM 5.7L and 6.4L HEMI engines power similar cars and trucks, with the larger engine usually being an upgrade option. This makes the comparison common as many wonder which engine is the best fit.

In this guide we’re going to compare everything between the two engines: performance, tuning potential, problems and reliability, specs, and price.

Dodge 6.4 vs 5.7 HEMI Specs, Performance, Reliability, MPG

Engine Specs Comparison

Engine5.7 HEMI6.4 HEMI
Displacement5.7L, 345 cu in6.4L, 392 cu in
ConfigurationV8V8
AspirationNaturalNatural
Block MaterialCast IronCast Iron
Head MaterialAluminumAluminum
ValvetrainOHV, 16 valveOHV, 16 valve
Bore x Stroke3.92″ x 3.58″4.09″ x 3.72″
Compression9.6:1 or 10.5:110.0:1 or 10.9:1
Horsepower340-395hp366-485hp
Torque (lb-ft)375-410tq429-457tq

Vehicle Applications

5.7 HEMI (345 HEMI)6.4 HEMI (392 HEMI)
2003-present Ram 1500/2500/35002014-present Ram 2500/3500/4500/5500
2009-present Dodge Challenger R/T2011-present Dodge Challenger SRT8, SRT, Scat Pack
2006-present Dodge Charger R/T2012-present Dodge Charger SRT8, SRT, Scat Pack
2004-present Dodge Durango2018-present Dodge Durango SRT
2005-present Chrysler 300C2012-2014 Chrysler 300C SRT8
2005-present Jeep Grand Cherokee2012-2020 Jeep Grand Cherokee SRT8, SRT
2006-2010 Jeep Commander 
2007-2009 Chrysler Aspen 
2005-2008 Dodge Magnum R/T 

The common them is that the 5.7 is a base engine in many models with the R/T badge. On the other hand, 6.4 HEMI engines often receive the SRT8, SRT, and 392 Scat Pack designations.

5.7 vs 6.4 HEMI Performance

Writing engine comparison guides can be challenging. Most engines are found in various models and years – as with these two HEMI engines. The following theme will apply to much of this article: it’s tough to get specific on a model and year basis. As such, we won’t be diving into 0-60, 1/4 mile times, or other specific performance factors.

There is still plenty to talk about when it comes to 6.4 vs 5.7 HEMI performance, though. The 6.4 HEMI generally offers an extra 75-100 horsepower over the 5.7 engine. Thanks to larger displacement the 392 is also good for an extra 60-80 lb-ft. Low-end torque is also about 70 lb-ft more, further widening the gap between the two. However, power and torque are a smaller difference on Ram trucks as the truck version is tuned for better economy and towing.

There’s no replacement for displacement. Clearly, this saying holds true in this comparison. These engines share similar design and tech, and the larger displacement HEMI simply has the edge. That’s not to say the 5.7L V8 is a slouch by any means. Rather, if you’re looking for all-out performance or towing then the 6.4 HEMI is the clear pick.

Winner: 6.4L HEMI

Aftermarket Potential

Larger displacement takes the win when it comes to tuning, modding, and aftermarket performance potential. If power and performance are the end goal the 6.4 Hemi is our pick.

The 5.7 Hemi is undeniably less expensive though. So the thought process could be: buy the smaller engine, use the money savings on upgrades, and end up with more power than the 6.4 Hemi. This certainly works, but mod for mod the 6.4 Hemi will of course always outperform the 5.7 so there isn’t much of a debate here.

Both of these engines have a ton of aftermarket support. Learn how much power you can make with our best 5.7 HEMI upgrades and 6.4 HEMI upgrade guides if you’re looking for more info.

Winner: 6.4 HEMI

Dodge 6.4 vs 5.7 HEMI Reliability

The 6.4 and 5.7 HEMI both offer good reliability overall. As with any engine, they’re prone to their share of problems and failures. We think both engines deserve average to above average remarks for reliability. Don’t expect Honda or Toyota-like maintenance and repairs, though.

Keep in mind we’re talking about performance engines. Repairs tend to be a bit more expensive when problems do occur. Basic maintenance items can also be pricier.

Which one is better, though? It’s impossible to say for sure. It’s likely both will offer similar reliability. Most of it simply comes down to maintenance and luck of the draw. Some engines hold up beyond 300,000 miles while others die much sooner.

Winner: Tie

Engine Problems

Issues between the two engines are pretty similar. Keep in mind – problems may appear worse or more common on the 5.7L V8. It’s the older and more popular engine on the road. As such, there’s more info and data points out there which can make problems seem more widespread.

Ultimately, both engines share many of the same common problems – such as the HEMI Multi-Displacement System (MDS). As stated previously, these engines offer similar reliability and which one is better often comes down to maintenance and some luck of the draw. Anyway, check out the below articles for more information on some common engine problems:

5.7 HEMI Engine Problems
6.4 Hemi HEMI Engine Problems

Price Comparison

The price difference when looking at similar model, trim, age, mileage, etc remains around the $5,000 to $10,000 mark, making the 5.7 Hemi the more affordable engine.

Furthermore, the 5.7 engines have been around since 2003. There isn’t a way to make a fair comparison in this case. It just means the 5.7 is the budget friendly option even if it means buying an older car. The age and higher production favors ownership costs when it comes to parts, replacement engines, so on.

Winner: 5.7 HEMI

Fuel Economy & MPG

All things equal, the 5.7 HEMI engine will deliver better fuel economy. It’s smaller and creates less power which means it uses less fuel.

Winner: 5.7 HEMI

Towing Capacity

Not only does the 6.4 Hemi offer more power and torque, but it’s also better tuned for towing. Low-end torque is a big improvement over the 5.7 Hemi. It’s generally going to offer the most towing capacity and pull similar weights with more ease. Although, the 5.7 isn’t a slouch and may be more than enough for many.

Winner: 6.4 HEMI

Summary

Chrysler, Dodge, and Ram offer the 6.4L and 5.7L HEMI engines in many similar models. The engines also share similar design and technology. It makes for a common discussion and comparison between the two. Picking the right engine for you can also be complicated since both engines have plenty to offer.

The saying, “there’s no replacement for displacement” holds true here. Dodge 6.4 HEMI engines simply offer more performance and towing. The 5.7 HEMI takes the win for price, parts availability, and fuel economy. They’re both pretty reliable engines, so that’s a wash.

In summary, if all-out performance or towing capacity is your goal then the 6.4 HEMI is likely the best choice. Those who want a great overall balance of performance, MPG, towing, and price will find joy in the 5.7L option. Either way, we believe it’s hard to go wrong with either engines.

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