6.6 CHEVY GM SPEED OF AIR LONG BLOCK (STD AUTO) 01-04 LB7 Core Charge Applies plus Core Container Charge (3000) of 500 Crate charge

If your 2001–2004 Duramax 2500HD or 3500HD needs a serious powerplant upgrade, the DFC Tow/Haul Series Long Block is built to handle the job. Designed for heavy towing, performance applications, and real-world work trucks, this engine packs premium components and proven durability into every build. Unlike a basic replacement, this long block includes performance-minded upgrades like a Stage 2 camshaft, Mahle Motorsports heavy-duty pistons, and Manton HD pushrods, all engineered to support up to 500 horsepower at the flywheel. You’ll also get the reliability of screw-in injector cups, a known weak point in stock LB7s, and added dowels in the crankshaft to keep your balancer and trigger gear rock-solid. Whether you're hauling loads cross-country or just want peace of mind under the hood, this engine is built to work hard and hold together under pressure. With a 5-year, 160,000 km warranty and nothing but name-brand internals throughout, it’s a serious upgrade for diesel owners who rely on their truck every day. From reliability to raw strength, this long block doesn’t cut corners, and neither should you. The DFC Diesel TH660104LB7SOALB Tow/Haul Series long block delivers a precision-built solution for 2001–2004 GM and Chevrolet trucks running the 6.6L LB7 Duramax. This engine includes all the upgrades found in DFC’s Street Series models, but steps it up with components chosen for higher horsepower and long-haul towing demands. At the core is a professionally machined and bored block, built to accept oversized pistons and outfitted with Mahle Motorsports HD units for added strength. A Stage 2 camshaft provides better valve timing for power and torque delivery, while Manton HD pushrods and upgraded valve springs improve valvetrain stability under load. Total Seal gapless rings increase compression and reduce blow-by, helping the engine operate efficiently under high stress. Added dowels in the crankshaft stabilize the harmonic balancer and trigger gear assembly, improving long-term engine balance and precision. Screw-in injector cups resolve a common failure point found in early LB7 models, adding peace of mind during extended operation. From daily towing to hard-working commercial use, this long block is engineered to support performance up to 500 HP while keeping durability at the center of its design.