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6.4 Hemi vs 6.7 Cummins In 2021– Which One is Better?

Are there any better brands for heavy-duty engines than Cummins or Chrysler? We don’t think so. The long discussion of which engine is better between the 6.4 Hemi vs 6.7 Cummins (from Chrysler and Cummins accordingly) is the perfect example.

For one, you have the 6.4 Hemi being a well-rounded diesel engine for power-hungry drivers.

It can handle heavy loads and pull other vehicles around with little to no effort.

Then you have the 6.7 Cummins, powering the Dodge RAMs of the world, always providing the reliability and power that makes Cummins stand out.

Both are exceptional in their own way, and here we’re going to explain that. While far from perfect, these engines are always worth a try – here’s why!

What to Know About the 6.4 Hemi?

A surprisingly new engine, the 6.4 Hemi gets the job done when it comes to carrying, pulling, and hauling weight.

Directly from Chrysler, it was first introduced in 2011 as one of the most powerful engines of its kind.

And to no surprise, it left a lot of mouths open (given Chrysler’s commitment to next-level quality).

You can find it on vehicles like the Dodge Ram 2500 and 3500, Dodge Charger, Dodge Challenger, Dodge Durango, Jeep Grand Cherokee, and Chrysler 300.

Which 6.4 Hemi is the Best?

The SRT8 model would be the most popular, given it uses the V8 engine and outputs a whopping 485 HP at its maximum. This matches the 470 ft-lbs of torque.

It was improved from previous versions, like the R/T Max with 470 HP output, making it a more potent alternative (ideal for trucks).

The engine is supposed to go from 0 to 60 MPH in less than 4 seconds when mounted on a Dodge Charger.

And mounted on a truck, it can tow upwards of 16,000 pounds without any issue.

Does that sound like a great deal? It sure does for us.

6.4L Cummins Specs

  • Horsepower: 366-485 HP
  • Torque: 429-475 lb-ft.
  • Displacement: 392cc
  • Cylinders: 8
  • Valves per cylinder: 2
  • Fuel type: Gasoline
  • Engine Weight: 500 lbs
  • Date of Production: 2011

What to Know About the 6.7 Cummins?

Cummins has been dropping premium engines for several decades, but the 6.7L Cummins from 2007 sets the pace.

You can find it mounted on vehicles like the Dodge Ram (2500 and 3500), Dodge Dakota (select few), and Jeep Wrangler (select few).

It is a monster of an engine, one of the heaviest and biggest overall – giving it a great hauling and towing capacity.

Which 6.7 Cummins is the Best?

The Turbocharged 2021 version of the 6.7L Cummins is the best without a doubt. Mounted on RAM 3500, it outputs a total of 420 HP with little effort.

This version was improved from the previous 6.7L Cummins engines providing no more than 385 HP.

That means you can get a boost of up to 40 HP, depending on the year you pick.

Apart from that, it is a decently fast engine. Mounted on a RAM 2500, it can reach 60 MPH of speed within 6 seconds.

That’s exceptional for its size and vehicle compatibility.

As for towing capacity, it will let you haul things as heavy as 19,000 pounds. That’s other-worldly for a truck engine like this.

When it comes to truck engines, few can handle the 6.7 Cummins cool factor.

6.7L Hemi Specs

  • Horsepower: 305-420 HP
  • Torque: 600-900 lb-ft.
  • Displacement: 408 cc
  • Cylinders: 6
  • Valves per cylinder: 4
  • Fuel type: Diesel
  • Weight: 1,050 lbs.
  • Date of Production: 2007

Factors to Consider Between the 6.4 Hemi vs 6.7 Cummins

Now that you have a clearer idea of what they offer in general let’s compare them.

We compare the 6.4 L Hemi vs 6.7 L Cummins by considering the Dodge RAM as the vehicle where they are mounted.

But we may also mention the different experiences when mounted on other cars.

Either way, here are some factors to consider:

Horsepower

We used to ride horses, giving cars a measurement of power based on how many horses they resemble. Both of these engines replace hundreds of horses each.

More specifically, you get up to 485 HP from a 6.4 Hemi (on a Dodge Charger). That’s A LOT. But when mounted on a RAM 2500, it gives a total of 370 HP.

A RAM 2500 with a 6.7 Cummins doesn’t stay too far behind, getting to 420 HP with ease. That’s an improvement of 50 HP compared to its Chrysler competitor.

In short, you should go for the 6.7 Cummins if you’re expecting higher power – as it is generally bigger.

Torque        

Torque refers to the total acceleration capacity of the engine, with higher torque, higher acceleration, and thus higher horsepower and speed (in general).

When mounted on a Dodge RAM, both engines perform exceptionally well. But while a 6.4 Cummins offers 420 lb-ft. of torque, the 6.7 Cummins can reach a whopping 900 lb-ft.

This may change in the year of production, as older models tend to provide less torque on both engines.

But you still get the sense that the 6.7 Cummins is slightly more torque-oriented, giving it a boost in acceleration (helpful in rugged terrain and when towing).

Fuel Efficiency

Despite being made for heavy-duty trucks, the 6.4 Hemi vs 6.7 Cummins fuel mileage is decent on both sides. Having said that, there’s a slight difference between them.

For example, the 6.4 Hemi boasts the MDS (Multi-Displacement System) that promotes fuel efficiency.

By shutting down cylinders when the vehicle is idle or not needing too much power. This reduces the amount of fuel used, offering an excellent 15 miles per gallon).

On the other hand, the 6.7 Cummins uses diesel, so it tends to burn through more.

But it still gets the job done at a decent pace, not burning more than 17 miles per gallon.

If you’re really worried about efficiency, then the 6.7 Cummins would be your best bet, given its use of diesel.

Towing Capacity

How big of a vehicle can each engine handle? It all comes down to how much weight they can tow.

As a relatively small engine for its power delivery, the 6.4 HEMI doesn’t stay behind with a surprising 16,000 pounds of towing reach.

This mainly depends on the road quality and elevation, but you can pretty much haul any large-sized truck with this engine.

You’ll find the 6.7 Cummins offering an impressive 19,000 pounds of towing capacity.

This comes at no surprise, given the bigger size and overall higher power and torque of the engine.

It can easily tow two or three vehicles at once (if it were possible).

Don’t dismiss the 6.7 Cummins engine if you’re towing a lot – as it can handle an astonishingly high sum.

Payload Capacity 

When mounted on a RAM 2500, the 6.4 Hemi can handle over 4,000 pounds. On a RAM 3500, its capacity can reach 7,600 pounds with ease.

Meanwhile, the RAM 2500 with a 6.7 Cummins doesn’t handle more than 3,100 pounds.

A RAM 3500 with the same engine will rarely go over the 3,900 pounds of payload limit.

It is surprising, given the 6.7 Cummins offers more towing capacity.

But not a secret why, as the 6.4 Hemi is a lighter engine, so it doesn’t have to power up that much weight.

For consistent carrying of materials, you may find the 6.4 Hemi better.

Durability   

There’s no secret both engines perform AMAZINGLY well when it comes to mileage.

On one side, you get the 6.4 Hemi delivering 250,000 miles. A RAM 2500 can easily reach this milestone even without significant issues, thanks to Chrysler quality.

On the other side, you’ll find the 6.7 Cummins offering up to 350,000 miles.

That’s why this engine is the preferred choice of most towing truck manufacturers, as it gets the job done for the long haul.

Their durability will depend on what strain they’re put on and how much maintenance they receive.

But this will give you an idea of how far they can go in a single RAM 2500 lifespan.

Reliability

If you need an engine that goes the extra mile without needing much upkeep, the 6.4 Hemi will keep you happy.

It requires essential maintenance like filter cleaning and general oil changes to stay healthy and pushing. Apart from that, it rarely suffers any issue to mention.

The 6.7 Cummins is not an unreliable engine in the slightest, but this one tends to suffer a few more issues.

These include head-gasket failure and fuel dilution. These may take a few hundred or thousands to fix, apart from the general maintenance.

Also, the EGR cooler tends to fail from time to time.

Overall, you’ll want to go for the 6.4 Hemi as it delivers way fewer issues over time.

A lack of problem isn’t assured, but you can rest more deeply with a RAM boasting one of these.

Price and Operating Costs

How much does each engine cost out of the gate? And how much will it cost over time?

At first, the 6.4 Hemi tends to be more expensive. It is a newer engine from Chrysler. Given its recency, it demands newer and more complex pieces.

But that’s not all – the engine comes with excellent technologies for fuel efficiency and extra reliability, making it less cheap at first.

But over time, the 6.4 Hemi tends to demand few expenses. It is so reliable and rarely gets into trouble, so it will cost only the fuel to operate.

You may need the occasional part replacement, but it is rare.

Then you get the 6.7 Cummins. This is a way cheaper engine despite its bigger size and higher general power.

But it is understandable, as it lacks reliability features and doesn’t boast the same technologies that increase overall manufacturing prices.

Over time, it may cost a bit more given its occasional problems.

Depending on where you live, you may also find that diesel costs more than gas, so it may also affect overall operating costs.

In general, you will have to pay more for a 6.4 Hemi than a 6.7 Cummins at first. But over time, the costs flip, as the Hemi tends to be more reliable and demand fewer upkeep costs.

6.4 L Hemi vs 6.7 L Cummins – Which One to Choose?

As you can guess, it won’t be easy to find out which engine you should go for (given you’re looking for a Dodge RAM).

But the factors above will make it easier. For that reason, consider these points:

  • If you want power, go for the 6.7 Cummins: it is the most potent by far, especially when it comes to towing operations.
  • If you prefer reliability, go for the 6.4 Hemi: it will keep your car running with fewer issues over the long run, requiring less money to keep running.

In a general sense, each engine has its ups and downs. While the 6.7 Cummins is a bit more durable, it is the 6.4 Hemi that will give you fewer headaches.

Apart from that, you will find the 6.4 Hemi more capable of carrying heavy payloads, but the 6.7 Cummins wins at towing.

And lastly, the 6.4 Hemi uses gasoline while the 6.7 Cummins powers up with diesel.

That should be an essential point to mention, given there’s not always availability of the same fuel options everywhere.

Bottom Line

It all comes down to your desired application. For example, if we were to pick, we wouldn’t hesitate to go for the 6.7 Cummins if we needed to tow a high number of vehicles.

But in case we needed more hauling capacity, the 6.4 Hemi would be our first choice.

Either engine will be a great choice nonetheless.

So, what are you getting between the 6.4 Hemi vs 6.7 Cummins?

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