6.6-Liter Duramax Engines

The Duramax engine is a joint venutre of GM & Isuzu.

LB7 (VIN "1") Engine was installed from 2001-2004.


LLY (VIN "2") Engine was installed from 2004-2005.


LBZ (VIN "D") Engine was installed from 2006-2007.


LMM (VIN "6") Engine was installed from 2007-2011.


LML (VIN "8") Engine was Installed from 2011 to current.


6.6L Duramax Engines to fit Chevrolet/GMC Pickup Truck from 2001-2014


Engine Identification


To determine the correct part number and configuration available, please gather the VIN (Vehicle Identification Number).




  • Silverado 2500HD, Silverado 3500HD

  • Sierra 2500HD, Sierra 3500HD

  • Kodiak C4500, Kodiak C5500, Kodiak C6500

  • Topkick C4500, Topkick C5500, Topkick C6500


Depending on the model this may be all that is needed. 

If you have a C4500, C5500 or C6500, additional information will be needed to determine the correct engine.


  • Assembled in the USA.

  • Blocks and crankshafts are 100% magnaflux tested to avoid cracked components.

  • Aluminum cylinder heads are dyed to check for cracks.Crankshafts are checked for size and micro-polishedto OEM specifications.

  • If necessary, it is re-ground re-nitrated and micro-polished to OEM specifications.

  • Connecting rods have new bushings installed and both large and small end are remachined to OEM specifications.

  • All heads get new valves and are vacuum tested to ensure the quality of the valve job.

  • All heads are pressure tested.

  • Core plugs are 100% stainless steel to avoid corrosion.

  • NPD replaces 100% internal wear items includingrings, bearings, bushings, gaskets and seals. 

Click on Pictures to View Options for Bare Long Block 6.6 L Duramax Engines