Featured Product

Custom Built Cummins® Replacement Long Blocks

Available for 3.9L, 5.9L and 8.3L Cummins® engines

  • Long Block Assembly
  • Part #: RP1336
  • For 8.3L Cummins 6 cylinder engines with single thermostat.

Made to Match Engine Specifications

A premium replacement choice for multiple applications ranging from light trucks to a wide variety of agricultural, construction and industrial engines. Reliance Cummins B and C series engine long block assemblies will give you access to high-quality parts in multiple convenient options.

All specifications and tolerances are checked and verified throughout the build process and are backed by a limited parts warranty. We have many configurations on the shelf that are ready-to-ship, some as soon as the next business day. With a quick turnaround time, these engines will spend less time out of commission and more time working – right where they need to be!

Option 1: New

Long Block Replacement

When you demand flexibility and convenience, ordering a long block from Reliance guarantees you will receive all new components without the hassle of a core return. These long blocks are 100% new and are sold outright.

Each new long blocks assembly is completely new and built from the bare block up using Reliance high-quality parts to create a long block specific to the desired equipment application.

Backed by 6-month limited parts warranty.

Option 2: Reman

Long Block Engine Replacement

Remanufactured, or reman products are designed to be as good as new at a substantially reduced price.

Backed by a 90-day limited parts warranty.

Option 3: DIY

(Do-It-Yourself) Long Block Kits

Now you have the option of building the long block yourself or receiving one already assembled. Long block kits have all the new parts and components needed to assemble a complete long block.

To learn more about Reliance's Cummins Long Block options, download flyer and contact your sales representative.

*Please Note: Next day product shipping does not apply to all configurations, contact your sales representative for specific availability. Ships FOB. All manufacturer names, numbers, symbols, and descriptions are for reference only. It is not implied that any part is the product of the manufacturer - Cummins® is the registered trademark of Cummins Inc, Columbia, Indiana.