The 6.4 HEMI Dodge vs. 5.7 HEMI. The 5.7L and 6.4L HEMI engines from Chrysler/Dodge/Ram power comparable cars and trucks. As a result, many people are curious about which engine is the best fit. Finally, both the 6.4 and 5.7 HEMI engines are likely to have plenty to offer most owners. It can be difficult to choose between two excellent engine options, but don’t worry. We compare the 6.4 vs 5.7 HEMI engine specs, reliability, performance, price, and more in this guide.
*The 345 HEMI and 392 HEMI engines are also known as the 5.7L and 6.4L HEMI engines, respectively. These figures denote the engine’s displacement in cubic inches. In this article, we will refer to the engines by these names.
Dodge HEMI Engine Specifications
The following table compares the specs of the 5.7 and 6.4 HEMI V8 engines:
The 5.7 and 6.4 HEMI engine specifications are straightforward. They have a lot in common, especially when it comes to engines from the same year. In any case, both have a V8 HEMI pushrod design with two valves per cylinder. Both the 345 HEMI and 392 HEMI engines use cast iron blocks with aluminum heads.
For the time being, we’ll refrain from revealing all of the horsepower and torque figures. Of course, the 6.4 HEMI is the superior engine. It has the advantage due to its greater displacement and output. There is more to consider when comparing the power and torque curves of 5.7 and 6.4 HEMI engines. This will come up in a few sections when we talk about performance.
*2009+ The 5.7 HEMI engine received a significant update. MDS and variable valve timing were two of the most significant updates. This technology is also used in 6.4 HEMI engines. The point is that older 345 HEMIs are a little different because they lack this technology.
What Vehicles Use HEMI Engines?
The following years and models have 6.4 vs. 5.7 HEMI engines:
As shown above, the 5.7 HEMI engine is available in a few models that do not have the 6.4L engine. It’s also the older engine, having been introduced in 2003, whereas the 6.4 HEMI didn’t arrive until 2011. However, Chrysler has offered the 6.4L as a crate engine under the name 392 HEMI since 2007.
In any case, the 5.7 is a standard engine in many models bearing the R/T badge. 6.4 HEMI engines, on the other hand, are frequently given the SRT8, SRT, and 392 Scat Pack designations.
HEMI V8 Performance 5.7 vs. 6.4
Writing engine comparison guides can be difficult. Most engines, like these two HEMI engines, come in a variety of models and years. Much of this article will be based on the following theme: it’s difficult to get specific on a model and year basis. As a result, we won’t get into 0-60, 1/4 mile, or other specific performance metrics.
When it comes to 6.4 vs. 5.7 HEMI performance, there is still plenty to discuss. The 6.4 HEMI engine typically produces 75-100 horsepower more than the 5.7 engine. The 392 has an extra 60-80 lb-ft of torque due to its larger displacement. The 5.7 has about 70 lb-ft more low-end torque than the 5.7, further widening the gap between the two. However, the difference in power and torque is smaller on Ram trucks because the 392 truck version is tuned for better economy and towing.
There is no substitute for displacement. This is clearly true in the 5.7 vs 6.4 HEMI comparison. These engines are similar in design and technology, with the larger displacement HEMI simply having the advantage. That is not to say that the 5.7L V8 is a slouch. Rather, if you want all-out performance or towing, the 6.4 HEMI is the clear choice.
The 6.4L HEMI came out on top.
HEMI 392 vs 345 Potential for the Aftermarket
Please forgive a few duplicate comments as this is the same concept as above. When it comes to tuning, modding, and aftermarket performance potential, larger displacement wins. If you want power and performance, the Dodge 6.4L V8 is the way to go.
We compared 2016 Dodge R/T Challengers with the 5.7 HEMI engine to those with the 6.4 HEMI R/T Scat Pack. The price difference is approximately $5,000 to $10,000, with the 392 HEMI being the more expensive option (as you likely guessed).
Purchase a 345 HEMI and use the leftover funds to upgrade, and you will almost certainly end up with the more powerful engine. It’s time to address some of the numerous counter-arguments. If you apply the same modifications to a 6.4L V8, it will become more powerful. Furthermore, no matter how many upgrades you add to the 5.7 HEMI, it will never be as powerful as the 6.4L.
Aside from that, both of these engines have an abundance of aftermarket support. Whether you go with the 345 or 392 engine, you’ll have no trouble finding what you’re looking for. If you need more information, check out our best 5.7 HEMI upgrades and 6.4 HEMI upgrade guides.
6.4 HEMI is the winner.
Dodge 6.4 vs. HEMI 5.7 Reliability
We’ll start with a simple topic: reliability. We wrote in-depth articles about engine reliability and common issues. For those interested in learning more, the links are just below in the next section. In this article, we’ll only scratch the surface and go over some fundamentals.
Both the 6.4 and 5.7 HEMI provide excellent overall reliability. They, like any other engine, are prone to problems and failures. We believe that the 5.7 and 6.4 HEMI deserve average to above-average reliability ratings. However, don’t expect Honda or Toyota-style maintenance and repairs.
Keep in mind that we’re discussing performance engines. When problems arise, repairs are typically more expensive. Basic maintenance items can also be more expensive.
But which one is superior? It’s impossible to be certain. We believe that the 6.4 HEMI and 5.7 HEMI will provide comparable reliability. The majority of it is simply down to upkeep and luck of the draw. Some 6.4L engines last for more than 300,000 miles, while others fail much sooner. The same is true for the Dodge 345.
Tie for first place
5.7L and 6.4L V8 Engine Issues
The problems with the two engines are very similar. Keep in mind that problems on the 5.7L V8 may be worse or more common. It’s the more common and older engine on the road. As a result, there is more information available for the 5.7 HEMI, which can make problems appear more widespread than for the 6.4 HEMI. On the contrary, there are more 345s with high mileage available.
Related : The 4 Typical GM 2.2 Ecotec Engine Issues
5.7 Hemi vs. 6.4 Hemi Cost
We briefly discussed the 5.7 vs. 6.4 HEMI price in the section on aftermarket performance. When comparing similar models, trims, ages, mileage, and so on, the price difference remains in the $5,000 to $10,000 range. It is not always true because other factors can influence price. Regardless, the 5.7 HEMI is the less expensive option.
Furthermore, 5.7 HEMI engines have been available since 2003. In this case, a fair comparison with the 6.4L V8 is impossible. It simply means that the 5.7 is the more cost-effective option, even if it means purchasing an older vehicle. The 345 HEMI also benefits from its age and higher production when it comes to parts, replacement engines, and so on.
5.7 HEMI is the winner.
345 vs 392 HEMI MPG/Fuel Economy
Because it is impossible to be extremely specific, this is a fairly brief topic. The fuel economy of a 5.7 vs. 6.4 HEMI is determined by a variety of individual factors. The year, model, drivetrain, conditions, driving habits, and so on all play important roles. However, if everything else is equal, the 5.7 HEMI engine will provide better fuel economy.
However, there are times when the 6.4 HEMI engine outperforms the 5.7L engine in terms of MPG. Is MDS technology available in the Dodge car or truck? This technology is available in some Dodge 5.7 HEMI engines but not in others. A 392 with MDS is a different story than a 345 without MDS.
Nonetheless, we could debate which engine in which configuration provides the best fuel economy all day. The point, however, remains. All else being equal, the smaller 345 cubic inch engine should deliver better MPG.
5.7 HEMI is the winner.
Towing Capacity of HEMI
When it comes to 6.4 vs. 5.7 HEMI towing capacity, the concepts remain hazy. There are far too many configurations that influence towing as much as or more than the engine itself. In any case, you guessed it. When it comes to towing, Dodge 6.4 HEMIs are the better choice.
It not only has more power and torque, but it is also better tuned for towing. The low-end torque is a significant improvement over the 392 cubic inch engine. It will typically have the greatest towing capacity and will be able to pull similar weights with greater ease. The 5.7 V8 isn’t a slouch, though, and may be more than enough for many.
6.4 HEMI is the winner.
Dodge 345 vs 392 HEMI Comparison
The 6.4L and 5.7L HEMI engines are available in a variety of models from Chrysler, Dodge, and Ram. The engines are also similar in terms of design and technology. It allows for a common debate and comparison between the two. Choosing the right engine for you can also be difficult because both engines have a lot to offer.
“There is no replacement for displacement,” as the saying goes. Dodge 6.4 V8 HEMI engines simply outperform the 5.7 HEMI in terms of performance and towing. The 5.7 HEMI wins in terms of cost, parts availability, and fuel economy. They’re both fairly reliable engines, so it’s a tie.
To summarize, if all-out performance or towing capacity are priorities, the 6.4 HEMI is likely the best option. Those looking for a great overall balance of performance, MPG, towing, and price will be pleased with the 5.7L V8. In any case, we believe the 345 or 392 HEMI engines are hard to beat.
