TH591998SOALBHD Tow/Haul HD Series Speed of Air Long Block (STD/Auto)

Features:

• Fits 1998 5.9L Cummins 24V Storm Block
• Rated for up to 900 horsepower
• Wagler connecting rods for extreme durability
• Balanced rotating assembly ensures smooth operation
• Fluidamper reduces engine vibration
• Heavy-duty flexplate included for added strength
• Stage 3 camshaft for improved performance
• Includes Total Seal gapless piston rings
• Ceramic-coated piston crowns resist heat damage
• Cometic MLS head gasket for superior sealing
• Backed by 5-year / 160,000 km warranty
• Built for towing, hauling, and street use

Built for the Grind, Tuned for Serious Power

If you’re pushing your 1998 5.9L Cummins 24V to its limits with heavy towing or high-performance tuning, the DFC Diesel Tow/Haul HD Series Speed of Air Long Block gives you a foundation that’s not just durable—it’s downright overbuilt. This isn’t your average reman. It’s a purpose-driven long block designed for truck owners who live in the 650–800 horsepower range, but still want the ability to stretch up to 900 HP at the flywheel. Whether you’re pulling a loaded trailer over the pass or dialing in your tune for weekend performance, this long block is built to handle it all without flinching.

Serious Hardware Where It Counts

At the heart of the Tow/Haul HD build are Wagler connecting rods, a balanced rotating assembly, and a Fluidamper harmonic balancer—all premium upgrades over even the Tow/Haul standard. DFC didn’t stop there; a heavy-duty flexplate and a set of ceramic-coated pistons with dry film-coated skirts come standard to handle the heat and pressure of high-load applications. Like all DFC engines, it’s machined with industry-leading Rottler equipment and assembled using all new OEM or better components, including Total Seal gapless rings, a Cometic MLS head gasket, and either ARP or OptiTorque head studs. From street use to full-load towing, this engine is built to do it all—and do it reliably. Backed by DFC’s 5-year/160,000 km warranty, it’s the peace of mind you need when your Cummins is built to perform.

Fits: 1998 Dodge RAM 5.9L Cummins

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