2001-2004 GM Duramax 6.6L LB7 - DFC's Tow Haul HD Series Long Block engines and are built for enthusiasts that want to be capable of up to 900HP but that will regularly drive on the street and tow trailers between 500 and 750 HP. This model comes equipped with all the features of the Street Series and Tow/Haul Series but adds a set of Wagler Forged connecting rods, Wagler Stage 1 alternate firing camshaft, balanced rotating assembly, HD Flex Plate and ATI dampener. Comes with a 5-year/160,000km warranty throughout North America, however, are considered a severe duty application and require more frequent service intervals as stated in the warranty manual supplement for warranty coverage to be considered.