KORE6604505LLYLBCC Kore Series Calles Crankshaft Long Block (STD/Auto)

Features:

• Upgraded Callies Compstar-Durastar crankshaft included
• Deep DuraCase nitride treatment for durability
• Drilled rod journals for reduced inertia
• True Form fillet radii on all journals
• Keyed timing gear resists shearing
• Accepts OEM flywheels and flexplates
• Total Seal gapless piston rings included
• Professionally machined using Rottler equipment
• Tighter tolerances than OEM specifications
• 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 Compstar-Durastar crankshaft in place of the factory unit. This isn't a generic aftermarket swap either, the crankshaft features a deep DuraCase nitride treatment for enhanced wear resistance, along with True Form fillet radii across every journal to reduce stress concentration under load. Callies also drilled the rod journals for reduced inertia and easier balancing, and keyed the timing gear specifically to prevent shearing, a detail that matters once you're pushing this engine harder than stock. Because it retains OEM journal diameters, OEM stroke, and accepts OEM post and flange bolts along with OEM flywheels and flexplates, this crankshaft upgrade drops in without forcing you to source a bunch of specialty supporting parts. This long block gives 2004.5-2005 GM Silverado and Sierra 2500HD and 3500HD owners genuine bottom end strength alongside everything the standard KORE Series build delivers, all without the complexity of a fully custom rotating assembly.

Callies Engineering Details Built Into A Precision Remanufactured Long Block

The DFC Diesel KORE6604505LLYLBCC is a remanufactured long block engineered specifically for 2004.5-2005 GM Silverado and Sierra 2500HD and 3500HD trucks equipped with the 6.6L Duramax LLY engine, built around an upgraded Callies Compstar-Durastar crankshaft in place of the factory unit. This crankshaft is constructed from hardened 4340 steel with a deep DuraCase nitride treatment that enhances both durability and wear resistance over the life of the engine. The rod journals are drilled for reduced inertia and easier balancing, while every journal features True Form fillet radii polished to a 6Ra or finer finish. The crankshaft maintains a 3.898 inch stroke with OEM journal diameters and width, uses a dual keyed damper fit, and includes lead-in oil holes at the main bearings for improved cold start oil flow to the rod journals. Because it accepts OEM post and flange bolts along with OEM flywheels and flexplates, installation stays straightforward despite the upgraded internals. Beyond the crankshaft, this long block follows DFC's standard KORE Series remanufacturing process, machined using Rottler equipment for tolerances that exceed OEM specifications, and includes Total Seal gapless piston rings along with improved gasket sealing in common leak areas. Every engine is manufactured in an ISO 9001:2015 certified facility and backed by a 1 year, unlimited mileage manufacturer warranty.

Fitment: 2004.5, 2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

Notes:

• Built with an upgraded Callies Compstar-Durastar crankshaft, not the factory unit
• Crankshaft retains OEM stroke, journal diameters, and accepts OEM flywheels/flexplates
• 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

Install Instructions