6.4 Hemi vs 6.7 Cummins (Which One is More Better?)

6.4 Hemi vs 6.7 Cummins is always pop up when discussing heavy-duty performance truck engines. Both engines are two of the most potent engines currently serving high-performance vehicles.

They also cater to a wide range of vehicles and have been in the automotive space for decades. However, many people are still puzzled about which engine seems better in terms of everyday application benefits. If you are in this league, you’re just about to find out here. The information you need lies below.

In short, the main difference between 6.4L hemi ram and 6.7L cummins is that ram 6.4L hemi has more fuel efficiency and produce 410 HP with less Torque(429 lb-ft) whereas the 6.7L cummins produces higher Torque( 850 lb-ft) with low horsepower(370 HP).

You might also like to read our important guideline on dodge ram leveling kits problems.

6.4 Hemi Overview

Hemi engines, dating as far back as the 1950s, manufactured under Chrysler, are currently one of the most powerful engines in the automobile world.

6.4L Hemi being one of their products, has some features that are worth looking into, including its configuration, which is V8, its cylinder head made of aluminum, and its incredible weight of 500 lbs.

Looking at the design of this engine, what seems to be the most captivating and most profound characteristically deviating feature compared with other versions of the Hemi like that of the 5.7L is its 90 degrees cylinder back orientation.

6.7 Cummins Overview

Cummins have been around since 1919 and are some rugged engines that commonly prop up in conversations about engine durability, strength, and overall performance.

Some of the key standard features include a 420 maximum Horsepower, an electronically-controlled throttle, and a massive 1,071 lbs of weight.

It currently services the 4th and, now, the 5th generation of Ram trucks and is the perfect heavy-duty engine for people who want ruggedly in action.

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6.4 Hemi vs 6.7 Cummins Comparison Table

6.4 Hemi Engine 6.7 Cummins Engine
Uses a naturally-aspirated gasoline engine Uses a Turbo diesel engine
6.4L 6.7L
Up to 480 horsepower output 400 horsepower, despite being powered by diesel.
Generates 429-475 ft-lb of torque Generates between 850-1000 lb-ft of torque
Engine design material is cast iron The engine is manufactured using compact graphite iron
Utilizes a cam-in-block variable valve timing(VVT) Utilizes connecting rods made of forged steel
VVT uses a hydraulic cam phasing system This phasing system is missing in 6.7 Cummins
Features Multi-Displacement System(MDS) technology Features an improved exhaust valve
Engine saves fuel by restricting flow into the engine at unneeded times. Features a Bosch CP4.2 with a maximum injection pressure of 29,000 psi
Used in performance vehicles like Ram, Dodge Charger, Dodge Challenger SRT8, and others. Services high-performance trucks.

Reliability of 6.4 Hemi and 6.7 Cummins

Here are the features that make the 6.4 Hemi and 6.7 Cummins a reliable option:

6.4 Hemi Reliability

It is a V8 that runs on a naturally-aspirated gasoline engine that offers you up to 485 horsepower and torque output between 429-475 ft-lb.

Talking about reliability, this engine can handle any amount of load and will still keep up its resilient optimal performance in extreme weather conditions.

The engine block is built with cast iron and also features piston cool jets.

The good side of the 6.4L Hemi and what makes it one of the most reliable truck engines is that it can easily last up to 250 000 miles, requiring only little maintenance and check-up.

In short, the engine, by design, is meant to exceed a decade-long use. Does this outmatch the 6.7L Cummins? Well, there’s only one way to know; check below.

6.7 Cummins Reliability

The 6.7 Turbo Cummins can dish out a fantastic 400 hp, which is quite astounding for a diesel-powered engine. You can also expect anything between an impressive 850-1000 lb-ft of torque.

The 6.7 Cummin has been reliably servicing trucks for years. The good side is that they like the 6.4 Hemi, which requires little maintenance and provide you with that extra output of a truck when you need it.

The engine features an improved exhaust valve paired with a rocker’s arm. Besides this, it also features a Bosch CP4.2 that provides an injection pressure of up to 29,000 psi.

In addition to this, its cooling capacity is quite effective and functions to keep the engine in good shape.

6.4 Hemi and 6.7 Cummins Towing Capacity

6.4 Hemi Towing Capacity

With towing capacity referring to how much weight your truck can pull, the 6.4 Hemi does quite an exciting job in providing enough power to the trucks it partners with.

For example, the maximum towing capacity of the 6.4L Hemi is 16 320 lbs for Ram 2500 of the 2019 model.

However, you need to be mindful that towing heavy cargo inclined upward for extended periods can limit the speed of your 6.4 Hemi engine to about 35 mph to keep it from revving.

Many factors were put together to provide the 6.4 with its impressive towing capacity that is not just suitable but percent for performance vehicles.

However, it fares better in this regard when compared to 6.7 Cummins, that services high-performance vehicles. Well, let’s find out.

6.7 Cummins Towing Capacity

The 6.7 Cummins offers the high-performance trucks the service, a towing capacity up to 19780lbs on vehicles of the 2019 ram 2500.

They also feature an auto-level rear suspension that helps the vehicle adapt very easily to the positional change of loads or the vehicle’s position. If you will be doing a lot of towing, the Cummins engine is the best engine.

6.7 cummins vs 6.4 hemi Fuel Mileage

6.4 Hemi Fuel Mileage

The 6.4L Hemi engine is designed to significantly reduce gas consumption using its Multi-Displacement system technology.

It does this by shutting down the activity of 4 of its 8 engine cylinders in situations where power is not needed. 6.4 Hemi engines can be made to conserve fuel in the following ways:

Engine oil

Engine oils can manipulate the performance of an engine. This, in turn, imparts the fuel efficiency of the engine.

Another way to put this is that if you want to improve the mileage of your 6.4L Hemi, consistently change the engine

The engine oil buffers between its internal components and minimizes the friction between them. This way, the engine does less work and saves fuel.

Otherwise, you wouldn’t get the mileage you want, and your engine might go bad after a few years.

Air Filter

Air filters are quite crucial in that they supply clean air to vehicle engines, allowing them to run Without them, it’s easy for dust particles to get into the engine and damage them.

They also make the engine do more work and, in the process, consume a lot of fuel.

You can check the filter by placing it near a light looking to see through. If you can’t see through, you need to change the filter.

Tune the Engine

Constantly check the engine at different intervals. This may involve tuning the engine.

Tuning the engine of a 6.4L Hemi installs new performance features, one of which is improved gas mileage.

Tuning makes the engine run effortlessly. If they don’t, they’ll consume a lot of gas.

6.7 Cummins Fuel Economy

Not a lot needs to be said about the fuel mileage of the 6.7 Cummin, except that it offers users better fuel management and economy than the 6.4 Hemi.

It also outperforms Hemi 6.4L by having a higher Miles Per Gallon(MPG). Its MPG is rated at 17.5, compared to the 15.7 of 6.4 Hemi. This is what you get when they are tested on Dodge Ram 2500.

6.7L Cummins and 6.4L Hemi Weight Comparison

Weight of 6.4 Hemi

The 6.4 Hemi engine weighs 500 lbs. Since the weight of a car plays an essential role in its performance, this 500lbs is perfect for producing the power needed to move the heavy performance trucks the engine is found in.

Dodge 6.7 Cummins Weight

The 6.7L Cummins engine weighs 1060lbs as its net weight. They are highly efficient and contribute to the displacement of their service vehicles.

Compared to the 6.4 Hemi, it produces more power but is less efficient in propelling vehicles to go uphill.

This is due to the force required to push it through. The 6.4 Hemi has the edge over the Cummins in this area.

6.4 Hemi or 6.7 Cumming : Which One is Better?

There’s an ongoing cold war between the engines, 6.4L Hemi and 6.7L Cummins, as people are always looking to know which one is better. This isn’t surprising, as they’re both outstanding engines.

Nonetheless, they differ in certain areas. Depending on what you are looking for, we can help you highlight certain features that make each engine stand out.

After that, you may then choose what is a priority to you.

Pros of 6.4 Hemi 

Gasoline is easier to obtain

The 6.4L Hemi engine runs on gasoline, so you can easily find them around, in petrol stations or fuel stations. On the other hand, getting diesel is not as common and could commit some tasks into your hands.

Less inexpensive fuel

Cummins engines run on diesel, which is relatively more expensive than the gas that Hemi runs on. So, for maintenance cost, Hemi wins it here and is a better engine.

Better torque and horsepower

The cylinder head intake manifold is now built to be vehicle-specific. At low RMPs, the intake valve shuts. At higher RPMs, increased horsepower is generated.

Drawbacks of 6.4 Hemi

Heat losses

Due to the large size of this combustion engine, it experiences a higher heat loss compared to smaller engines.

Advantages of 6.7 Cummins Engine

Towing capacity is higher

Both engines do excellent jobs when it comes to towing. However, pick the Cummins if you’re looking for which engine will perform better. This is because they have a higher towing capacity.

Better fuel efficiency

It has an excellent fuel to energy ratio, placing it ahead of the Hemi 6.7L. Hence, you don’t spend much on fuel when running with this engine. This explains why they have better MPG compared to Hemi engines.

Drawbacks of Dodge 6.7 Cummins

Fuel dilation problem

Even though this is a common problem among many engines, especially after extended usage, it seems to be more frequent in Cummins engines. If you’re skeptical about dealing with issues like this, you should stay away from this engine model.

People Also Ask

Are the best diesel engines 6.7 Cummins?

Cummins makes a bold statement when it comes to ruggedness and durability. This could be because they were originally designed to be used for heavy-duty trucks.

Hence, it is the perfect truck for rough handling and heavy use.

Cummins engines are now obtainable in the general automobile industry, while they still retain these two main features – toughness and durability.

So, if you’re looking for an engine where you can get maximal torque and increased horsepower paired with a good compression ratio, 6.7 Cummins is a recommended option.

Are MDS features bad for truck engines?

A short and direct answer is no. It is quite understandable that there are several concerns because out of the eight cylinders that truck engines have, only 4 operate when MDS is activated.

However, the major problem is the uneven wear that could happen due to the heat produced by cylinders that are in operation being counteracted by the cold ones that are dormant.

Manufacturers are aware of this, so the valve seats are modified to keep MDS issues under control.

How many miles will a Hemi 6.4L run?

Hemi engines are precisely built to be powerful. They have been serving lots of truck users for decades.

A Hemi 6.4L engine will last at least 250000 miles under normal use. The cost of painting them also isn’t so expensive.

Final Words

Having carefully researched Hemi 6.4 and Cummins 6.7, we have highlighted the strengths and weaknesses of both engine models.

The article shows that the 6.7 Cummins engine is a preferred choice in terms of maximum towing capacity, expected mileage, and torque output.

They also have a higher MPG compared to what’s obtainable from Hemi 6.7. Notwithstanding, the 6.7 Hemi has a higher edge in areas like horsepower and maximum payload capacity, of which they offer users higher numbers.

Also, they’re just as durable as the Cummins and require little maintenance. Hence, picking one from both engines would be based on proposed usage.

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