TH599497SOALBHD Tow/Haul HD Series Speed of Air Long Block (STD/Auto)

Features:

• Fits 1994–1997 5.9L Cummins 12V engines
• Rated for up to 900 horsepower
• Wagler connecting rods for extreme strength
• Balanced rotating assembly for smooth operation
• Includes Fluidamper for vibration control
• Heavy-duty flexplate included for added durability
• Includes all Street and Tow/Haul upgrades
• Built for towing and high-power street use
• Total Seal gapless piston rings standard
• Cometic MLS head gasket for maximum sealing
• Backed by 5-year/160,000 km warranty

For the Diesel Enthusiast Who Pushes Limits

If you're building a 1994–1997 5.9L Cummins 12-valve that lives under heavy loads and isn’t afraid of horsepower, the DFC Diesel TH599497SOALBHD Tow/Haul HD Series Long Block is exactly the foundation you need. This isn’t just a reman—it’s a purpose-built, high-performance long block designed for trucks that tow hard and drive harder. While it includes all the upgrades from the Street and standard Tow/Haul series, the HD version turns it up a notch with serious internal fortifications like Wagler connecting rods, a Fluidamper harmonic balancer, and a heavy-duty flexplate. These upgrades work together with a balanced rotating assembly to keep things smooth and strong when the power curve peaks and the trailer weight is heavy.

Engineered for High Horsepower and Daily Reliability

Built to handle up to 900 horsepower at the flywheel, this long block isn’t just about brute force—it’s also designed to be streetable and tow-ready between 650–800 horsepower. Ceramic-coated pistons and dry film-coated skirts help fight heat and friction under boost, while ARP or OptiTorque head studs lock it all down. It comes fully machined and balanced with every component carefully spec’d to meet or exceed OEM tolerances. The complete assembly includes a remanufactured head, top-end gasket kit, pushrods, rockers set to spec, and all-new internals. While this is a serious engine for demanding setups, it’s still backed by DFC’s 5-year/160,000 km (100,000 mi) warranty—just keep up with the more frequent service intervals required for severe duty use. If your Cummins is built to tow like a machine and hit the throttle without mercy, this is the long block that can take it—and then some.

Fits: 1994, 1995, 1996, 1997 Dodge RAM 5.9L Cummins 12V

Product Image Note: Some images may be representative.