TH660607LBZSOALB Tow/Haul Series Speed Of Air Long Block (Standard/Auto)

Features:

• 5-year / 160,000 km warranty coverage
• Built for towing and hauling up to 500HP
• Includes Stage 2 performance camshaft
• Mahle Motorsports heavy-duty pistons installed
• Manton heavy-duty push rods for strength
• HD valve springs for improved durability
• ARP or OptiTorque head studs included
• Total Seal gapless piston rings standard
• Added crankshaft dowels for balancer stability
• EDM doweled oil pump gear for reliability
• Cylinder heads resurfaced and magnafluxed
• Complete top-end gasket kit included

Built To Pull Strong And Last Long

When your 2006-2007 GM or Chevrolet 2500HD or 3500HD with the 6.6L Duramax LBZ is used for serious towing and hauling, you need more than a stock replacement. The DFC Diesel Tow/Haul Series Long Block is built with the strength and upgrades to handle demanding loads up to 500HP at the flywheel. This engine includes all the proven improvements from DFC’s Street Series, then adds heavy-duty enhancements like Mahle Motorsports pistons, Manton HD push rods, and reinforced valve springs for long-term reliability under load. The Stage 2 performance camshaft boosts both pulling power and throttle response, giving your truck the extra edge it needs on steep grades or when hauling full trailers. ARP or OptiTorque head studs lock down cylinder pressure, while Total Seal gapless piston rings improve efficiency and sealing. It is backed by a 5-year or 160,000 km warranty, so you can run your truck with confidence in any work or recreational setting. This is the build you want when you need your engine to work as hard as you do.

Engineered For Heavy Loads And Lasting Performance

The DFC Diesel TH660607LBZSOALB Tow/Haul Series Long Block starts with the same foundation as the Street Series, using a fully remanufactured block that is machined and bored for next over-sized pistons. Mahle Motorsports heavy-duty pistons are installed for maximum durability under high cylinder pressures. The rotating assembly benefits from added crankshaft dowels that improve harmonic balancer and trigger gear stability, reducing the risk of movement under extreme loads. A Stage 2 performance camshaft and Manton HD push rods work with reinforced valve springs to provide smooth, consistent operation in high-demand towing and hauling applications. ARP or OptiTorque head studs ensure a secure seal under heavy boost, while Total Seal gapless piston rings enhance compression and reduce blow-by. Cylinder heads are fully reconditioned with new seats, guides, valves, and stem seals, then resurfaced and magnafluxed for reliability. Every build is completed with a full top-end gasket kit, making installation straightforward and helping ensure your engine is ready for years of dependable service.

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 Series is built for towing and hauling applications up to 500HP
• Includes all upgrades found in the Street Series build
• Engine is a remanufactured long block, not a complete drop-in
• Equipped with Mahle Motorsports heavy-duty pistons for durability
• Features a Stage 2 performance camshaft for added power
• Manton heavy-duty push rods and HD valve springs included
• Added crankshaft dowels for improved harmonic balancer stability
• Built with all new OEM or equivalent internal components
• 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.