6.0L Power Stroke vs. 6.7L Cummins vs. 6.6L Duramax


Power Stroke

6.0L Power Stroke


6.7L Cummins

6.6L Duramax LLY

Production Years:

2003 - 2007

2007.5 - present

2004 - 2006





Block/Head Material:






Inline 6



6.0 liters, 365 cubic inches

6.7 liters, 408 cubic inches

6.6 liters, 403 cubic inches

Compression Ratio:



17.5:1 (Lowered to 16.8:1 in 2006)

Bore x Stroke:

3.74 x 4.13 inches

4.21 x 4.88 inches

4.06 x 3.90 inches

Injection System:

Hydraulic electronic unit injection (HEUI)

high pressure common rail

High pressure common rail, CP3 injection pump


Variable Geometry Turbocharger (VGT)

Variable geometry turbocharger (VGT)

Variable Geometry Turbocharger (VGT)


overhead cam, 4 valves per cylinder

overhead valve, 4 valves per cylinder

over head valve, 4 valves per cylinder


approx. 966 lbs


835 lbs (approx.)

Peak Horsepower:*

325 hp @ 3,300 RPM

350 hp @ 3,013 RPM

320 hp @ 3,000 RPM (2006 figures)

Peak Torque:*

570 lb-ft @ 2,000 RPM

650 lb-ft. @ 1,500 RPM w/ auto trans
610 lb-ft. @ 1,500 RPM w/ man trans

560 lb-ft @ 1,600 RPM (2006 figures)


The 5 speed Torqshift transmission that comes standard with the 6.0L Power Stroke is a definite strong point. The transmission features crisp, firm shifts and the Tow/Haul mode works much better and smarter than its competitor's. Some 6.0L are ridiculed for problems, but the 6.0L is a very strong and reliable engine with great towing characteristics.

One of the unique features of the 6.7L Cummins is the factory installed exhaust brake. The engine has proven to be a reliable design, much like the 5.9. Fuel economy seems to have suffered on the 6.7L when compared to the 5.9L, largely attributed to the engines increased displacement and a magnitude of emissions controls. In comparison to the 6.0L Power Stroke & 6.6L Duramax LLY, the 6.7L Cummins provides more peak power, but the others will have better fuel economy.

The Duramax LLY under went huge changes in 2006, which included a larger EGR, stronger bottom end components, and a increased maximum common rail injection pressure. As a result, the 2006 model has an additional 40 lb-ft. of torque and 10 horsepower over the previous LLY. The LLY is the first Duramax to recieve emissions controls.


2003 - 2007 Ford Super Duty; F250, F350, F450, F550, F650.

2007.5 - present Ram 2500 & 3500.

2004 - 2006 Chevrolet & GMC HD 2500 & 3500 trucks.


*Peak horsepower & torque refers to the highest advertised power output during the engine's production.




You may also be interested in the following articles:

6.7L Cummins vs. 6.7L Power Stroke

6.4L Power Stroke vs. 6.6L Duramax

5.9L Cummins vs. 6.6L Duramax