6.2L GM vs. 6.6L Duramax

GM Diesel - Old vs. New

The 6.2L GM diesel was designed and released as a fuel saver rather than a work horse. At the time of it's release, a big block gasser would outpull the 6.2L by a long shot. But a big block gasser was not capable of 20+ mpg, quite an achievement for any vehicle in the 80's. The 6.2L was designed as an economical alternative to the gas guzzling V-8's of the time period. As such, the engine is not considered to be as heavy duty as its competitors. Enter the 6.6L Duramax, an engine designed by a joint venture between Isuzu and GM. The first Duramax was released in 2001, and it signifies GM's decision to get serious about the diesel truck market. The Duramax is far more competitive than any previous diesel engine used in GM trucks. The current version of the Duramax lays down a whopping 765 lb-ft of torque, a far cry from the 240 lb-ft that the 6.2L was capable of.


6.2L GM

1982 6.2L GM Diesel

Duramax LML

2011 6.6L Duramax LML


6.2L GM V-8 diesel (Detroit Diesel)

6.6L Duramax LML V-8 (Isuzu + GM)

Years of Operation:

1982 - 1993

2011 model year - current


6.2L, 379 cubic inches

6.6L, 403 cubic inches


Naturally aspirated

Turbocharged & intercooled (VGT)

Block/Head Material:

cast iron/cast iron

Cast iron/aluminum


130 hp @ 3,600 rpm (1982)

397 hp @ 3,000 rpm (2011)


240 lb-ft @ 2,000 rpm (1982)

765 lb-ft @ 1,600 rpm (2011)


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