The 5.7- and 6.4-liter HEMI engines from Chrysler, Dodge, and Ram power comparable cars and trucks. As a result, the two engines are frequently compared because so many people are curious about which one is better.
Both the 6.4 and 5.7 HEMI engines have a lot to offer most owners in the long run. It’s difficult to decide between the two excellent engine options, though. Do not be alarmed. 6.4 vs 5.7 HEMI engine specs, reliability, performance, and more are all compared side by side in this guide.
When it comes to HEMI engines, the 345 and 392 designations are used interchangeably. In cubic inches, these are the engine’s displacement numbers. In this article, the engines will be referred to as by these names.
Dodge HEMI Engine Specs
The following graph compares the performance of the 5.7 and 6.4-liter HEMI V8 engines.
|Engine||5.7 HEMI||6.4 HEMI|
|Displacement||5.7L, 345 cu in||6.4L, 392 cu in|
|Block Material||Cast Iron||Cast Iron|
|Valvetrain||OHV, 16 valve||OHV, 16 valve|
|Bore x Stroke||3.92″ x 3.58″||4.09″ x 3.72″|
|Compression||9.6:1 or 10.5:1||10.0:1 or 10.9:1|
The 5.7- and 6.4-liter HEMI engine specs are uncomplicated. When looking at engines from the same year, they have a lot in common. They both have V8 HEMI pushrod engines with two valves per cylinder, so that’s something in common. In addition, the cast iron blocks and aluminum heads found in the 345 and 392 HEMI engines are shared.
For the time being, we’ll refrain from disclosing any additional information on the engine’s power and torque specs. The 6.4-liter HEMI, on the other hand, is significantly more powerful. It has the advantage due to its greater displacement and output. There’s a lot more to learn about the power and torque curves of the 5.7 and 6.4 HEMI engines. We’ll talk about performance in a few sections where this comes up.
*2009+ The 5.7-liter HEMI engine has undergone a significant makeover recently. Two of the most significant changes were the addition of MDS and variable valve timing. This technology can be found in the 6.4 HEMI engine as well. To summarize, older 345 HEMI engines lack this technology, making them unique.
What Cars Use the HEMI Engines?
The following years and vehicle models use 6.4-liter HEMI engines instead of 5.7-liter ones:
|5.7 HEMI (345 HEMI)||6.4 HEMI (392 HEMI)|
|2003-present Ram 1500/2500/3500||2014-present Ram 2500/3500/4500/5500|
|2009-present Dodge Challenger R/T||2011-present Dodge Challenger SRT8, SRT, Scat Pack|
|2006-present Dodge Charger R/T||2012-present Dodge Charger SRT8, SRT, Scat Pack|
|2004-present Dodge Durango||2018-present Dodge Durango SRT|
|2005-present Chrysler 300C||2012-2014 Chrysler 300C SRT8|
|2005-present Jeep Grand Cherokee||2012-2020 Jeep Grand Cherokee SRT8, SRT|
|2006-2010 Jeep Commander|
|2007-2009 Chrysler Aspen|
|2005-2008 Dodge Magnum R/T|
Some models don’t have the 6.4L engine, so the 5.7 HEMI is an alternative. It’s also an older model, having been introduced in 2003, as opposed to the newer 6.4 HEMI in 2011. Although the 6.4L was discontinued in 2007, Chrysler continues to offer it as a crate engine under the model name of the “392 HEMI.”
Whatever the case may be, the 5.7-liter V8 is a common powerplant in R/T-badged vehicles. 6.4 HEMI engines, on the other hand, are frequently designated as SRT8, SRT, or 392 Scat Pack.
5.7 vs 6.4 HEMI V8 Performance
It’s not always easy to write an engine comparison guide. As with these two HEMI engines, most engines can be found in a variety of models and years. Much of this article will focus on the fact that it’s difficult to pinpoint a specific model or year. As a result, we won’t be looking at specific performance metrics like 0-60 mph or 1/4 mile times.
When it comes to HEMI performance, there’s still a lot to discuss between the 6.4 and 5.7 models. The 6.4 HEMI typically offers 75-100 hp more than the 5.7. With the 392’s increased displacement, you’ll get an additional 60-80 lb-ft of torque.
More low-end torque than the 5.7 means a bigger gap between the two. There is less of a disparity between the Ram 392 truck and the other Ram models when it comes to horsepower and torque.
Displacement cannot be substituted for in any way. The 5.7 vs 6.4 HEMI comparison proves this adage to be true. Despite the fact that these engines are similar in terms of design and technology, the HEMI’s larger displacement gives it the advantage.
That’s not to say, however, that the 5.7L V8 is a dud. When it comes to power and towing, the 6.4 HEMI is hands-down the best option.
Winner: 6.4L HEMI
392 vs 345 HEMI Aftermarket Potential
Please excuse the fact that some comments are being posted twice because the concept is the same. More displacement means more room for aftermarket performance upgrades like tuning and modification. The Dodge 6.4L V8 is our top pick if you’re looking for raw power and speed.
We despise going down this path, but it’s necessary from time to time. We compared 2016 Dodge R/T Challengers with the 5.7-liter HEMI and the 6.4-liter HEMI R/T Scat Pack based on their respective mileage. The 392 HEMI is the more expensive option, with the price difference ranging between $5,000 and $10,000. (as you likely guessed).
Spend the money on a 345 HEMI and upgrade it with the money you save. You’ll have the more powerful engine at the end of the process. It’s only fair to mention a few of the many opposing viewpoints that can be made here. A 6.4L V8 can be made more powerful by applying the same modifications. The 5.7 HEMI will never be as powerful as the 6.4 no matter how many upgrades you add.
Then there’s the aftermarket support for both of these engines. Whichever engine you go with, you’ll have no trouble finding what you’re looking for. If all you care about is the market and support for the engines, then it’s a tie.
Winner: 6.4 HEMI
Dodge 6.4 vs 5.7 HEMI Reliability
The topic of reliability is one that we can easily get into. The reliability of engines and common engine problems were topics of our in-depth articles. Those interested in learning more can do so by clicking on the links provided just below in the next section. We’ll only scratch the surface of the subject matter in this article by talking about the essentials.
The 6.4- and 5.7-liter HEMI engines are equally reliable in general. They, too, are prone to issues and failures, just like any other type of engine. The 5.7 HEMI and the 6.4 HEMI, in our opinion, are both reliable. However, don’t expect maintenance and repair costs to be comparable to those of a Honda or Toyota.
Remember, we’re discussing high-end race engines. When something goes wrong, repairs are more expensive. The cost of routine maintenance, such as oil changes and tire rotations, can add up.
But which one is superior? There’s no way to know for sure. The reliability of the 6.4 HEMI and the 5.7 HEMI is expected to be comparable, according to our research. The majority of it is down to routine upkeep and good fortune. Engines with 6.4-liter displacement can last for more than 300,000 miles before needing replacement. A similar statement can be made in regards to the Dodge 345
5.7L & 6.4L V8 Engine Problems
There are a lot of similarities in the problems that arise when using the two engines. Keep in mind that issues with the 5.7L V8 may be exacerbated or become more prevalent. It’s the car with the more traditional engine, and it’s the one most people are familiar with.
As a result, there is more information available on the 5.7 HEMI, making problems appear more widespread than with the 6.4 HEMI. Contrary to popular belief, there are a greater number of 345s with extensive mileage available.
Hemi 5.7 vs 6.4 Hemi Price
Aftermarket performance was briefly discussed in the section on 5.7 vs 6.4 HEMI pricing. When comparing similar models, trims, ages, mileage, and so on, the price difference is typically between $5,000 and $10,000. This isn’t always the case because there are a variety of other factors involved. The 5.7 HEMI, on the other hand, is the less expensive engine.
5.7 HEMI engines have also been around since 2003. The 6.4L V8 can’t be fairly compared to this engine because of the differences in displacement. So, even though buying an older car will save money, going with the 5.7 is the better value. The fact that the 345 HEMI is older and more common means that parts, replacement engines, and the like are easier to come by.
Winner: 5.7 HEMI
345 vs 392 HEMI Fuel Economy/MPG
Since it’s impossible to be incredibly specific, this will be a short topic. The difference between HEMI fuel economy ratings of 5.7 and 6.4 mpg is dependent on numerous factors. Years, models, drivetrains, weather, driving habits, and other factors all have a significant impact. However, if every
thing else is equal, the 5.7-liter HEMI engine will deliver better fuel efficiency.
However, there are times when the 6.4-liter HEMI engine delivers better fuel economy than the 5.7-liter unit. Is there MDS technology in a Dodge vehicle? This technology is present in some Dodge 5.7 HEMI engines, but not all of them. When comparing a 392 with MDS to a 345 without MDS, the results are quite different.
Despite this, the debate over which engine, in which configuration, provides the best fuel economy could last all day. But the point is still there. All things being equal, the MPG advantage of the smaller 345 cubic inch engine should be evident.
Winner: 5.7 HEMI
When it comes to the 6.4-vs.-5.7 HEMI towing capacity, the concepts remain hazy. A vehicle’s configuration has a greater impact on towing than the engine itself. Anyway, it’s obvious. For towing, Dodge 6.4 HEMI engines are the better choice.
It has more oomph and torque, but it’s also been fine-tuned to handle towing duties. The 392 cubic-inch engine’s low-end torque is vastly improved. It’s going to be able to tow the most weight and pull it with the least amount of effort. However, the 5.7-liter V8 isn’t a slouch and should be adequate for most buyers.
Winner: 6.4 HEMI
Dodge 345 vs 392 HEMI Summary
The 6.4-liter and 5.7-liter HEMI engines are available in numerous models from Chrysler, Dodge, and Ram. The designs and technologies of the engines are also very similar. It’s a great topic for debate and comparison because of this. Choosing between the two engines can be difficult because they both have a lot to offer.
Displacement can never be replaced, as the old adage goes. The 6.4-liter HEMI engine from Dodge simply outperforms the 5.7-liter HEMI in terms of power and towing capacity. When it comes to cost, parts availability, and efficiency, the 5.7 HEMI engine is the clear winner. Because both engines are very dependable, we believe the HEMI 6.4 vs 5.7 is a tie.
If you’re looking for maximum power and/or towing capacity, the 6.4 HEMI is the engine for you. The 5.7L V8 is an excellent choice for drivers looking for a good mix of power, fuel economy, towing capacity, and price. No matter which HEMI engine you choose, we believe you can’t go wrong with either the 345 or 392 model.
What are your thoughts on them? Is one something you’re thinking about doing?
Tell us what you think in the comments section below!