7.8L Duramax 7800

Related Topics:

LB7 Duramax 6600

LBZ Duramax 6600

LLY Duramax 6600

LMM Duramax 6600

LML Duramax 6600



Return to Duramax Diesel Specs.


7.8L Duramax LG4

Inline 6 Duramax





The Duramax 7800 is based on the Isuzu 6H series inline 6 cylinder turbodiesel. The engine was offered by General Motors in their Chevrolet Kodiak and GMC Topkick models from 2003 until 2009, when GM pulled out of the medium duty market. The engine was offered in a variety of power options during this time period, ranging from a 200 hp/520 lb-ft model all the way up to a 300 hp/860 lb-ft model. Isuzu continues to manufacture this engine for many industrial applications. The engine produces peak torque at a low 1,450 rpm and has a governed speed (fuel shutoff under load) of 2,400 rpm.



7.8L Duramax Specs


7.8L Duramax 7800 (Isuzu 6H-Series), inline 6 cylinder turbodiesel.

Years Produced:

2003 - 2009 for Chevrolet Kodiak and GMC Topkick


475 cubic inches, 7.8 liters

Head/Block Material:

Cast iron cylinder heads, cast iron engine block.

Compression Ratio:

16.0 : 1 standard, 17.5 : 1 for 300 hp model.


4.53 inches


4.92 inches


Turbocharged & intercooled (air-to-air).


Direct injection, high pressure common rail.


Single overhead camshaft (SOHC) , 4 valves per cylinder.

Engine Weight:

Approx. 1,400 lbs dry.

Max Engine Speed:

2,400 rpm.

Peak Horsepower:

215/230/250/275/300 hp @ 2,200 rpm (several ratings available).

Peak Torque:

520 - 860 lb-ft @ 1,450 rpm.