TH591998SOALB Tow/Haul Series Speed of Air Long Block (STD/Auto)

Features:

• Fits 1998 5.9L Cummins 24V Storm Block
• Rated for towing and up to 700 HP
• Includes stage 3 camshaft upgrade
• 60lb heavy-duty valve springs (94–98)
• Manton HD pushrods for added strength
• Total Seal gapless piston rings standard
• Ceramic coated piston crowns for heat resistance
• Dry film coated piston skirts reduce friction
• Cometic MLS multi-layer steel head gasket
• ARP or OptiTorque head studs included
• Professionally machined and balanced assembly
• 5-year / 160,000 km limited warranty

Heavy-Duty Power for Real-World Hauling

If your 1998 5.9L Cummins-powered Ram is built to tow hard, run strong, and take abuse without flinching, the DFC Diesel TH591998SOALB Tow/Haul Series Long Block is the foundation you want under the hood. Designed specifically for the 24-valve Storm Block, this engine doesn’t just replace your worn-out setup—it upgrades it with proven performance features made for high-load use. Whether you’re pulling trailers day in and day out or want a bulletproof long block for your next build, this package is built to handle up to 700 horsepower while keeping things reliable enough for daily duty. And unlike a basic reman, everything inside has been carefully selected, machined, and assembled to tighter tolerances using name-brand components you can trust.

Upgrades Where They Matter Most

This build includes everything from the Street Series—like Total Seal gapless rings, Cometic MLS head gaskets, and either ARP or OptiTorque head studs—but adds a host of enhancements built specifically for towing and high-performance applications. A stage 3 camshaft improves airflow and midrange torque, while 60lb heavy-duty valve springs and Manton HD pushrods keep the top end in check under boost. The pistons are treated with ceramic-coated crowns and dry film coated skirts to manage heat and reduce wear—two must-haves in high-output, high-stress builds. From the rear aluminum freeze plug to the resurfaced and magnafluxed cylinder head, every inch of this long block is engineered with purpose. And with a 5-year/160,000 km (100,000 mi) warranty, you’ve got long-term peace of mind to match the engine’s capability. This is the long block that lets your Cummins work as hard as you do.

Fits: 1998 Dodge RAM 5.9L Cummins

Product Image Note: Some images may be representative.