6.4L Power Stroke vs. 6.7L Cummins vs. 6.6L Duramax

2008 Model Year Diesel Pickup Comparison

 

 

6.4L Power Stroke

6.7L Cummins

6.6L Duramax LMM

Production Years:

2008 - 2010

2007.5 - present

2007.5 - present

Manufacturer:

International Navistar

Cummins Inc

DMAX (GM, Isuzu joint venture)

Block/Head Material:

Cast iron engine block, cast iron cylinder heads

Cast iron engine block, cast iron cylinder heads

Cast iron engine block, aluminum cylinder heads

Configuration:

V-8

Inline 6

V-8

Displacement:

6.4 liters, 390 cubic inches

6.7 liters, 408 cubic inches

6.6 liters, 403 cubic inches

Compression Ratio:

16.7:1

17.3:1

16.8:1

Bore x Stroke:

3.86 x 4.13 inches

4.21 x 4.88 inches

4.06 x 3.90 inches

Injection System:

High pressure common rail

High pressure common rail

High pressure common rail

Aspiration:

Twin sequential turbochargers

Variable geometry turbocharger (VGT)

Variable geometry turbocharger (VGT)

Valvetrain:

Overhead valve, 4 valves per cylinder

Overhead valve, 4 valves per cylinder

Overhead valve, 4 valves per cylinder

Weight:

approx. 1,150 lbs

1,050 - 1,150 lbs

approx. 835 lbs.

Peak Horsepower:

350 hp @ 3,000 RPM

350 hp @ 3,013 RPM

365 hp @ 3,100 RPM

Peak Torque:

650 lb-ft. @ 2,000 RPM

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

660 lb-ft. @ 1,800 RPM

Notes:

• Factory equipped twin turbochargers.
• Best-in-class tow capacity for the 2008 model year.

• Factory equipped exhaust brake system.
• 68RFE 6 speed automatic transmission has proved to be significantly more reliable than previous Chrysler transmissions.
• Available with a manual transmission, but only with a detuned motor.

• Highest horsepower and torque for the 2008 model year.
• Allison 1000 6 speed automatic remains an industry favorite.