DFC Diesel SS661723L5PSOALB Street Series Speed Of Air Long Block (Standard/Auto) | 2017-2023 GM/Chevrolet 2500HD/3500HD 6.6L Duramax L5P

Features:

• 5-year / 160,000 km warranty coverage
• Built with brand new OEM components
• Upgraded ARP or OptiTorque head studs
• Total Seal gapless piston rings included
• Precision machined for perfect factory fit
• Improved sealing in common leak areas
• Professionally bored for oversized pistons
• Re-manufactured heads with new valves
• Custom EDM doweled oil pump gear
• Woodruff keyed camshaft for reliability
• Complete long block with top-end gaskets
• Ideal for daily driving and work trucks

Take Your Duramax To The Next Level

If you want an engine that works as hard as you do, the DFC Diesel SS661723L5PSOALB Street Series Speed Of Air Long Block is built to deliver. Designed for 2017-2023 GM and Chevrolet 2500HD and 3500HD trucks with the 6.6L Duramax L5P, this remanufactured long block is the perfect heart for your daily driver, tow rig, or workhorse. It comes packed with smart upgrades to fix the common weak points in stock engines, giving you the peace of mind that your truck is ready for the long haul. Backed by one of the strongest warranties in North America, you know you’re getting an engine that’s made to last. Every build includes ARP or OptiTorque head studs, Total Seal gapless piston rings, and precise machining to make sure everything fits and runs like it should. You get more than just factory reliability here, you get a setup that’s tuned for durability under real-world use. Whether you’re pulling heavy loads, putting in highway miles, or just want a truck that won’t let you down, this Street Series Long Block delivers the performance and dependability you need.

Engineered For Lasting Power And Reliability

The DFC Diesel Street Series Long Block starts with a professionally machined block, bored to accept the next oversized piston for a precision fit. Every part inside meets or exceeds OEM specifications, from the brand new pistons and rings to the valves, seals, and gaskets. Cylinder heads are fully re-manufactured with new seats, guides, and stem seals, then resurfaced and magnafluxed to ensure strength and consistency. You also get upgrades like a Woodruff keyed camshaft and a custom EDM doweled oil pump gear to maintain long-term reliability. Improved sealing methods target common leak points so you spend less time in the shop and more time on the road. The complete long block comes with the top end gasket kit to make installation smoother and faster. Built using advanced Rottler machining equipment, each engine is crafted with the accuracy and attention to detail that serious truck owners demand. The result is a 6.6L Duramax L5P long block that is every bit as tough as the trucks it powers.

Fits: 2017, 2018, 2019, 2020, 2021, 2022, 2023 GM/Chevrolet 2500HD/3500HD 6.6L Duramax L5P

Notes:

• Compatible with 2017-2023 GM/Chevrolet 2500HD and 3500HD 6.6L Duramax L5P
• Street Series is a long block assembly, not a full drop-in engine
• Includes top-end gasket kit but other parts may be required for installation
• Head studs will be ARP or OptiTorque depending on availability
• Covered by 5-year / 160,000 km (100,000 mi) limited warranty
• Warranty coverage requires following DFC’s maintenance schedule
• Oil change intervals reduced to 6,500 km or 3 months during warranty
• Commercial and severe-duty use may have stricter service requirements
• Professional installation is strongly recommended for performance and warranty compliance
• Order must match your transmission type (Standard or Automatic)
• Long block does not include turbocharger, fuel system, or external accessories
• Core return and freight shipping terms apply; inspect upon delivery

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.