KORE660104LB7LBCC Kore Series Calles Crankshaft Long Block (STD/Auto)

Features:

• Upgraded Callies aftermarket crankshaft included
• Stronger than factory Duramax crankshaft
• Total Seal gapless piston rings included
• For use with automatic and manual transmission
• Professionally machined using Rottler equipment
• Tighter tolerances than OEM specifications
• All new pistons, rings, bearings, and gaskets
• Improved gasket sealing in common leak areas
• Built in ISO 9001:2015 certified facility
• 1 year unlimited mileage warranty

Addressing The Duramax's Most Catastrophic Failure Point

Ask any Duramax owner about the scariest failure on this platform, and a broken factory crankshaft usually tops the list. The DFC Diesel KORE Series Callies Crankshaft Long Block was built specifically to take that risk off the table, pairing DFC's remanufacturing process with an upgraded Callies aftermarket crankshaft in place of the factory unit. Callies has built a real reputation in the diesel performance world for crankshafts that hold up where the stock LB7 crank simply wasn't designed to, especially under sustained load or increased power. This long block gives 2001-2004 GM Silverado and Sierra 2500HD and 3500HD owners a genuine strength upgrade at the bottom end, not just a standard remanufactured replacement. Alongside the Callies crank, you're still getting everything the standard KORE Series long block delivers, including Rottler machined tolerances tighter than OEM, Total Seal gapless piston rings, and improved gasket sealing in this platform's known leak points. Whether you're rebuilding after a close call or building proactively before your LB7 ever lets you down, this long block gives you real peace of mind at the one failure point that worries Duramax owners most.

Callies Crankshaft Strength Built Into A Precision Remanufactured Long Block

The DFC Diesel KORE660104LB7LBCC is a remanufactured long block engineered specifically for 2001-2004 GM Silverado and Sierra 2500HD and 3500HD trucks equipped with the 6.6L Duramax LB7 engine, built around an upgraded Callies aftermarket crankshaft in place of the factory unit. This crankshaft upgrade directly addresses one of the LB7's most well known failure points, where the factory crank can break under sustained high horsepower or heavy load. Beyond the crankshaft, this long block follows the same remanufacturing process as DFC's standard KORE Series builds, machined using Rottler equipment for tolerances that exceed OEM specifications. The engine includes all new pistons, rings, bearings, gaskets, seals, valves, springs, hardened seats, stem seals, and cast guides, along with Total Seal gapless piston rings and improved gasket sealing methods in common leak areas. The long block ships as a complete short block assembly with the cylinder heads included, along with a complete top end gasket kit and silicone to finish the installation. As with DFC's standard long block, this unit does not include the front cover, rear cover, oil pump, upper or lower oil pan, oil pickup tube, rocker arms, pushrods, or valve bridges. Every engine is manufactured in an ISO 9001:2015 certified facility and backed by a 1 year, unlimited mileage manufacturer warranty.

Fitment: 2001, 2002, 2003, 2004 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LB7

Notes:

• Built with an upgraded Callies aftermarket crankshaft, not the factory unit
• Does not include front cover, rear cover, oil pump, upper or lower oil pan, oil pickup tube, rocker arms, pushrods, or valve bridges
• Component brands may vary by build based on parts availability, cannot be specially requested
• $500 shipping charge/$2,800 core charge 
• Engine shipping crate must be returned with core engine for full core credit
• Manufacturer warranty: 1 year, unlimited mileage
• Oil cooler replacement highly recommended, mandatory if prior engine had a bearing failure
• Injector replacement highly recommended on higher mileage or contaminated fuel engines
• Turbocharger replacement recommended over 125K miles, mandatory if shaft play present or engine was dusted
• Water pump replacement highly recommended if engine has over 125K miles
• Evans Waterless Coolant recommended upgrade for corrosion and boilover prevention
• This product cannot be shipped to California