6.0L Power Stroke vs. 5.9L Cummins vs. 6.6L Duramax

Power Stroke

6.0L Power Stroke


5.9L Cummins ISB


6.6L Duramax LBZ

Production Years:

2003 - 2007

1998 - 2007.5

2006 - 2007.5





Block/Head Material:






Inline 6



6.0 liters, 365 cubic inches

5.9 liters, 359 cubic inches

6.6 liters, 403 cubic inches

Compression Ratio:


16.3:1 (17.3:1 in HO version)


Bore x Stroke:

3.74 x 4.13 inches

4.02 x 4.72 inches

4.06 x 3.90 inches

Injection System:

Hydraulic electronic unit injection (HEUI)

Bosch rotary injection pump. Switched to high pressure common rail injection in 2003

High pressure common rail, CP3 injection pump


Variable Geometry Turbocharger (VGT)

Holset Turbocharger

Variable Geometry Turbocharger (VGT)


overhead cam, 4 valves per cylinder

over head valve, 4 valves per cylinder

over head valve, 4 valves per cylinder


approx. 966 lbs

1,150 lbs (approx.)

835 lbs (approx.)

Peak Horsepower:*

325 hp @ 3,300 RPM

325 hp @ 2,900 RPM (high output model)

360 hp @ 3,200 RPM

Peak Torque:*

570 lb-ft @ 2,000 RPM

610 lb-ft @ 1,600 RPM (high output model)

650 lb-ft @ 1,600 RPM


Stock torque to yield (TTY) head bolts proved to be a weak link. The overall engine design is good, though the emissions equipment proved to cause issues in some applications. Ford Power Stroke continues to outsell Cummins & Duramax. Overall a strong performer with good fuel economy. The Ford Torqshift 5-speed automatic has a good reputation for strength, crisp shifts, & appropriate shift timing.

Brute strength, builds torque at low RPM. Lots of aftermarket engine modifications available. More turbo lag than Ford & Chevrolet, and typically slower in stock form. Medium duty engine in light duty trim. The stock Dodge transmissions are significantly weaker than Ford or General Motors transmissions. They have a reputation of failure when engines are tuned to produce anything over the stock power rating.

Like the other 3 Duramax engines, a large portion of the diesel community ridicule the Duramax for its aluminum heads & small connecting rods. However, the LBZ is considered the "hot rod" of Duramax diesels due to its power potential when complimented with aftermarket tuning. The Allison 1000 6-speed automatic transmission remains a strong part of the Duramax package.


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

1998 - 2007.5 Dodge Ram 2500 & 3500 trucks.

2001 - 2004 Chevrolet & GMC HD 2500 & 3500 trucks.


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




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