DFC Diesel TH660607LBZSOALBHD Tow/Haul HD Series Speed Of Air Long Block (Standard/Auto) | 2006-2007 GM/Chevrolet 2500HD/3500HD 6.6L Duramax LBZ

Features:

• 5-year / 160,000 km warranty coverage
• Built to handle up to 900HP
• Ideal for towing 500-750HP regularly
• Wagler forged connecting rods installed
• Wager Stage 1 alternate firing camshaft
• Balanced rotating assembly for smooth operation
• Callies Compstar forged steel crankshaft
• ATI dampener for improved vibration control
• Heavy-duty flexplate for strength and durability
• ARP or OptiTorque head studs included
• Cylinder heads resurfaced and magnafluxed
• Complete top-end gasket kit included

Unmatched Power For Heavy Towing And Street Use

If you want an engine that can handle serious towing power while still being street-friendly, the DFC Diesel Tow/Haul HD Series Long Block is built to deliver. Designed for 2006-2007 GM and Chevrolet 2500HD and 3500HD trucks with the 6.6L Duramax LBZ, this build is capable of supporting up to 900HP at the flywheel. It is ideal for truck owners who regularly tow between 500 and 750HP but still want reliability for everyday driving. This engine includes all the proven upgrades from the Street Series and Tow/Haul Series, plus heavy-duty enhancements like Wagler forged connecting rods, a Wager Stage 1 alternate firing camshaft, and a balanced rotating assembly. The ATI dampener and HD flexplate improve stability and reduce vibration, while the Callies Compstar crankshaft adds unmatched bottom-end strength. With this combination of durability and performance, you can confidently take on steep grades, heavy trailers, and long hauls. Backed by a 5-year or 160,000 km warranty, this is an investment that pays off every time you turn the key.

Precision Built For Maximum Strength And Longevity

The DFC Diesel TH660607LBZSOALBHD Tow/Haul HD Series Long Block is engineered from the block up to meet the demands of high-horsepower towing and performance use. It begins with a professionally remanufactured block, machined and bored for next over-sized pistons to ensure a perfect fit. Wagler forged connecting rods provide exceptional strength under high load, while the Wager Stage 1 alternate firing camshaft helps balance cylinder pressure and improve torque delivery. A balanced rotating assembly, paired with a Callies Compstar crankshaft, ensures smooth, consistent operation at all power levels. The ATI dampener and HD flexplate add further stability to handle the increased stress of heavy-duty use. Cylinder heads are fully reconditioned with new seats, guides, valves, and stem seals, then resurfaced and magnafluxed for maximum sealing and reliability. Each build is finished with ARP or OptiTorque head studs and a complete top-end gasket kit, giving you everything needed for a clean, strong installation that will stand up to years of hard work.

Fits: 2006, 2007 GM/Chevrolet 2500HD/3500HD 6.6L Duramax LBZ

Notes:

• Designed for 2006-2007 GM/Chevrolet 2500HD and 3500HD with 6.6L Duramax LBZ
• Tow/Haul HD Series is built for up to 900HP capability
• Recommended for towing between 500-750HP regularly
• Includes all upgrades from Street and Tow/Haul Series builds
• Engine is a remanufactured long block, not a complete drop-in
• Equipped with Wagler forged connecting rods for extreme strength
• Wager Stage 1 alternate firing camshaft improves balance and torque
• Balanced rotating assembly for smoother, more consistent operation
• Includes ATI dampener and heavy-duty flexplate for added stability
• Callies Compstar crankshaft provides exceptional bottom-end durability
• Cylinder heads are resurfaced, magnafluxed, and fully reconditioned
• Backed by a 5-year / 160,000 km manufacturer warranty

Street Series vs Tow/Haul vs Tow/Haul HD

• Street Series: Ideal for daily driving, light work, and diesel enthusiasts. Focuses on reliability upgrades over stock, with head stud and sealing improvements.

• Tow/Haul Series: All Street upgrades plus added performance parts for higher load and towing power. Supports builds up to ~700 HP.

• Tow/Haul HD Series: The most robust option. Adds heavy-duty internals like Wagler rods and a balanced rotating assembly for 800+ HP capability.

Standard/Auto vs Standard vs Auto

• Standard/Auto: Compatible with both manual and automatic transmissions. Offers the most flexibility.

• Standard: Built specifically for manual transmission configurations.

• Auto: Built specifically for automatic transmission setups.