Driving Innovation In Diesel Performance

Long Blocks. Built for Cummins.

Shop Cummins long blocks by build intent—OE replacement, towing duty, street performance, and max-effort foundations. Select your option and click Shop to land on the correct product page.

Essential Reman
6.7 ESSENTIAL REMAN LONG BLOCK

Essential Reman Long Blocks

Stock-style reliability for OE replacement—choose 5.9L or 6.7L common rail and click Shop.

  • OE replacement foundation
  • Built for daily + towing
  • Clean, consistent assembly
  • Best value long block
Choose your engine
Shop Essential Reman
Precision Plus
19+ 6.7 COMMON RAIL CUMMINS PRECISION PLUS REMAN LONG BLOCK

Precision Plus Long Blocks

OEM+ long block foundation—built for consistency, durability, and a stronger starting point.

  • OEM+ replacement foundation
  • Premium consistency focus
  • Great base for upgrades
  • Built for long-term reliability
Shop Precision Plus
Heavy Hauler
Heavy Hauler 2019+ Long Block

Heavy Hauler Long Blocks

Tow-duty long blocks built for sustained load and heat—choose your platform and click Shop.

  • Best for towing/work trucks
  • Durability under load
  • Built for repeatable duty cycles
  • Long-term reliability focus
Choose your platform
Shop Heavy Hauler
Street Performance
Street Performance 6.7 Cummins Common Rail Long Block

Street Performance Long Blocks

Daily-driven performance foundation—ideal for mild-to-moderate upgrades and strong street manners.

  • Street-driven performance intent
  • Boost-ready foundation
  • Great for mild fueling/turbo
  • Balanced drivability focus
Choose your engine
Shop Street Performance
Performance Series
Performance Series 6.7 Cummins Common Rail Long Block

Performance Series Long Blocks

Built for higher output goals—choose your engine and tier to route to the correct long block.

  • Higher cylinder pressure intent
  • Built for performance upgrades
  • Choose standard / HP / Extreme
  • Match to turbo/fueling plan
Choose your build
Shop Performance Series
Predator
PREDATOR Long Block

Predator Long Block

High-output foundation built for serious performance goals and stronger supporting mods.

  • Built for big-power intent
  • Performance-focused foundation
  • Turbo/fueling upgrades ready
  • Max-effort build direction
Shop Predator
Enforcer
ENFORCER Deck Plate Long Block

Enforcer Deck Plate Long Block

Extreme-cylinder-pressure foundation—built for high boost, high power, and hard-use performance.

  • Deck plate strength
  • Extreme boost intent
  • High cylinder pressure support
  • Built for max-effort builds
Shop Enforcer
Knowledge Hub

Everything you need to know about D&J Cummins long blocks

D&J long blocks are organized by intent: Essential Reman for OE replacement, Precision Plus for OEM+ consistency, Heavy Hauler for towing duty cycles, Street/Performance builds for upgraded setups, and Predator/Enforcer for max-effort foundations. Use the selectors to route to the correct product and confirm inclusions before ordering.

  • Choose by intent firstEssential Reman for OE replacement, Heavy Hauler for towing duty, Street/Performance for upgraded builds, and Predator/Enforcer for max-effort setups.
  • Match 5.9 vs 6.7 correctlyCommon rail year ranges and configurations vary—route to the correct product and confirm sensors/emissions details on the product page.
  • Confirm what transfersAccessories and external components often transfer—review inclusions and requirements on the product page before ordering.
  • Break-in mattersPrime the oil system, verify oil pressure, and follow recommended heat cycles and early oil/filter service for long-term reliability.

FAQs

What is a Cummins long block and what’s included?

A long block typically includes the assembled engine block and internal rotating assembly with the cylinder head/valvetrain installed. External accessories and bolt-ons often transfer from your existing engine—verify the product page for exact inclusions.

How do I choose between 5.9L and 6.7L Cummins common rail long blocks?

Start with your truck’s engine family and year range. 5.9 common rail and 6.7 common rail can differ in sensors, emissions equipment, and calibration. Use the correct option for your platform to avoid fitment surprises.

What’s the difference between Essential Reman and Precision Plus long blocks?

Essential Reman targets stock-style reliability and OE replacement. Precision Plus is the OEM+ foundation—built for tighter consistency and a stronger starting point for long-term durability and upgrades.

Which long block is best for towing and heavy work?

For sustained load and heat, choose a Heavy Hauler style long block. It’s intended for work-truck duty cycles where durability and repeatability matter more than peak dyno numbers.

What’s the difference between Street Performance and Performance Series long blocks?

Street Performance is aimed at daily-driven performance and mild to moderate upgrades. Performance Series is built for higher cylinder pressure and more aggressive build goals—match it to your turbo/fueling plan.

What is a deck plate long block (Enforcer) and who is it for?

A deck plate build increases rigidity for high cylinder pressure applications. Enforcer-style long blocks are typically chosen for extreme boost, high horsepower goals, and hard-use performance builds.

Do I need tuning after installing a performance Cummins long block?

Often, yes—especially if your build includes changes to fueling, turbo sizing, or airflow. At minimum, confirm sensor/emissions compatibility and follow recommended break-in and calibration guidance for your configuration.

What should I inspect when a long block is delivered?

Inspect the crate before signing, document any damage with photos, and confirm the part number matches your order. Report freight damage immediately so the claim process is clean and documented.

*Fitment and outcomes vary by truck configuration, supporting mods, tuning, and duty cycle.