DFC Diesel TH590304STAUSOALB Tow/Haul Series Speed of Air Long Block Crate Engine (STD/Auto) | 2003-2004 Dodge RAM 5.9L Cummins

Features:

• 5-year, 160,000 km warranty included
• Built to handle up to 700 HP
• Includes ARP or OptiTorque head studs
• Stage 3 camshaft for towing performance
• Ceramic-coated pistons resist heat and wear
• Dry film coated skirts reduce friction
• 103lb or 60lb heavy-duty valve springs
• Cometic MLS head gasket seals under load
• HD Manton pushrods handle high pressure
• Gapless Total Seal rings reduce blow-by
• Precision-machined using Rottler CNC equipment
• Fits 2003–2004 5.9L Cummins (Auto/Std)

Take On Bigger Loads With Peace Of Mind

If your 2003-2004 Dodge 5.9L Cummins is built for serious work, the DFC Tow/Haul Series Long Block is the engine that can keep up. Designed with heavy towing and high-demand hauling in mind, this crate engine brings the strength and reliability that diesel owners count on. It includes all the proven upgrades from DFC's Street Series, plus even more enhancements built specifically for trucks running up to 700 horsepower. With a Stage 3 camshaft, heavy-duty Manton pushrods, and ceramic-coated piston crowns, it's engineered to run cooler and stronger under stress. You also get top-tier sealing thanks to the Cometic MLS head gasket and gapless Total Seal piston rings, which means you spend more time on the road and less in the shop. Whether you're pulling equipment, a trailer, or just want the confidence of added durability, this engine delivers in all the ways that matter. It's a solid investment for anyone who works their truck hard and needs dependable power every time the key turns.

Engineered To Push Power Without Pushing Limits

The DFC Diesel TH590304STAUSOALB Tow/Haul Series Long Block is a performance-built remanufactured engine crafted for high-stress, high-output applications. It starts with a professionally machined block and cylinder head, each serviced with Rottler CNC equipment to ensure flawless fit and function. Inside, you'll find ceramic-coated pistons with dry film coated skirts for reduced heat and wear during sustained load cycles. Valve spring upgrades depend on model year, with either 60lb or 103lb heavy-duty springs supporting the valvetrain through higher RPMs and towing loads. The Stage 3 camshaft enhances torque and drivability across the powerband, while Manton heavy-duty pushrods ensure strength in the valve system. ARP or OptiTorque head studs and a Cometic MLS gasket are included to lock in compression and eliminate sealing concerns. This engine is compatible with both standard and automatic transmissions, offering a straight-forward solution for serious builds needing long-term durability. Everything about this long block is designed to support hard use without compromising longevity.

Fits:  2003, 2004 Dodge RAM 5.9L Cummins

Notes:

• Core return may be required for purchase
• Designed for 2003-2004 5.9L Cummins engines
• Compatible with both automatic and manual transmissions
• Built to support towing and hauling up to 700 HP
• Includes all upgrades from the Street Series engine
• Valve spring spec depends on model year
• Long block does not include fuel system components
• Professional installation is strongly recommended
• 5-year, 160,000 km warranty coverage applies
• Some components may vary based on availability

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.