Duramax vs. Cummins Engines

Commercial Engine Comparison



Turbo Diesel Options


Cylinder Block


Cylinder Head

350 hp

Max. Horsepower

360-370 hp
700 lb-ft

Max. Torque

1,000 lb-ft



Duramax and Cummins engines have long been touted for their dependability and exceptional power. These machines power some of the industry’s hardest working trucks — from the Chevy Silverado 1500 to the Silverado 5500HD to the Ram 3500 Chassis Cab. So, which is right for your application? Read on to learn more about the Cummins vs. Duramax differences and similarities and to decide which is right for you!

About Duramax Engines

Duramax engines can be found in Chevrolet and GMC vehicles, such as the Chevy Silverado and GMC Sierra. Their high horsepower and torque outputs directly compete with Cummins engines, as well as PowerStroke. In addition to durability, Duramax engines are known for their quiet performance. The Duramax LP5 in particular is 38% quieter than previous versions. Currently, there are two Duramax engines in production: L5P (2017 – present) and LM2 (2019 – present).

  • All-New 3.0L Turbo-Diesel LM2: This brand-new engine powers vehicles like the Chevy Silverado 1500 and generates 277 hp and 460 lb-ft of torque.
  • 6.6L Duramax Turbocharged L5P: Offering V8 power, this engine produces 350 hp and 700 lb-ft and includes the following features:
    • Paired with the Allison 1000 Series 6-speed automatic transmission
    • Electronically controlled variable-geometry turbocharger
    • Exhaust Gas Recirculation System
    • Venturi Jet Drain Oil Separator
    • Cast-aluminum cylinder heads and cast-iron cylinder block
    • Cold-Start System for improved performance in cold climates
    • B20 biodiesel compatible
2019 Chevrolet Silverado 5500 at Construction Site

About Cummins Engines

Cummins engines are known for their power, reliability and durability, and are frequently found in hard-working commercial vehicles. The current incarnation is the Cummins 6.7L Turbo Diesel. This engine is available for the Ram 2500 and 3500 Heavy-Duty pickup trucks, as well as the RAM 3500, 4500, and 5500 Chassis Cabs. There are some slight differences in power, based on the truck body style:

  • 6.7L Cummins Turbo Diesel — Generates 370 to 400 hp and 850 to 1,000 lb-ft of torque
  • 6.7L Cummins Turbo Diesel (for Chassis Cabs) — Generates 360 hp and 800 lb-ft of torque

When you consider the many features of the Cummins engine, it’s not surprising that most drivers choose it when buying a new or used Ram truck. Here’s a quick look at what makes the Cummins engine unique from others:

  • 16.21: compression ratio
  • B20 biodiesel compatible
  • 6-cylinder inline engine
  • Exhaust brake function
  • Cast-iron block and cylinder heads
  • Holset HE351VE variable geometry turbocharger
  • Bosch high-pressure common-rail fuel system

If you do end up choosing a model with a Cummins engine, you may need to know how to identify an Aisin transmission.

2019 RAM Chassis Cab at Construction Site

Duramax vs. Cummins: Which is Right for Me?

The right engine for you depends on the type of truck you need. If you’re considering Duramax vs. Cummins engines, your choice is essentially GM vs. Ram. Take the 2019 Ram 5500 vs. 2019 Chevy Silverado 5500, for example. Both are chassis cabs and offer the following features:

Ram 5500:

  • Cummins® 6.7 turbo-diesel engine rated at 360 hp and 800 lb-ft of torque
  • Rust-through warranty coverage for 60 months/unlimited miles
  • Uconnect® 3.0

Chevy Silverado 5500: 

  • Duramax® 6.6L turbo-diesel V8 engine rated at 350 hp and 700 lb-ft of torque
  • Dual fuel tank capacity of 65 gallons
  • Available Chevrolet Infotainment System
Black 2019 GMC Sierra Parked Near Cliffs

Learn More About the Duramax vs. Cummins Difference Today!

Ready to test drive a pickup truck or chassis cab equipped with a Cummins or Duramax engine? Contact us at Lynch Truck Center to schedule an appointment near Milwaukee and Racine. We’ll give you a tour of our new and used inventory, as well as our new vehicle specials!

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