Product Description
Interstate-McBee M-4089950 Piston Kit (Standard Bore) – 03–04 5.9L Cummins 305HP
OEM-style standard-bore piston kit engineered for 2003–2004 5.9L Cummins ISB (305 HP). Each kit services one cylinder and includes the piston, hardened wrist pin, retainers/clips, and piston rings for a durable, direct-fit rebuild.
- Direct replacement: Fits 5.9L ISB common-rail 305 HP applications (see fitment notes).
- Standard bore (STD): For unbored factory cylinder size.
- Complete per-cylinder kit: Piston + pin + retainers/clips + ring set.
- Aftermarket value: Interstate-McBee quality at a lower cost vs. OEM.
Specifications
| Brand | Interstate-McBee |
|---|---|
| Interstate-McBee P/N | M-4089950 |
| OEM Cross-Reference | Cummins 4089950 |
| Bore Size | Standard (STD) |
| Kit Contents | Piston, hardened wrist pin, retainers/clips, piston rings |
| Sold | Individually (order 6 for a complete set) |
| Warranty | Interstate-McBee limited warranty (see details below) |
Vehicle Fitment
Always verify with your engine serial number (ESN) and VIN.
- 2003 Dodge Ram 2500/3500 5.9L Cummins (High Output 305 HP only)
- Early 2004 Dodge Ram 2500/3500 5.9L Cummins – Federal emissions 305 HP trucks
- Not for 2004 California emissions trucks (different piston)
- VIN quick check: 8th digit C = High Output (305 HP); 6 = Standard Output
What’s Included
- (1) Piston (STD)
- (1) Hardened wrist pin
- (2) Retainers/clips
- (1) Piston ring set
Install Notes
- Confirm engine HP/EMISSIONS configuration and ESN before ordering.
- Measure cylinder and check ring end-gap per Cummins service manual.
- Observe piston orientation and correct pin/clip installation.
Warranty
Interstate-McBee new engine parts are covered by a manufacturer warranty—typically up to 24 months from installation under normal use. Contact us for details specific to piston kits.
Why Buy From CPP Diesel
- ESN-verified fitment support from diesel specialists
- Fast shipping options and straightforward returns
- Large in-stock selection for Cummins B-series rebuilds
FAQ
Is this piston kit truly “STD” size?Yes—M-4089950 is a standard-bore kit for factory cylinder size (no overbore).
Will it fit every 2003–2004 5.9L Cummins?
It fits 305 HP applications only. For 2003, that’s the High Output trucks. For early 2004, it applies to federal emissions 305 HP trucks. It is not compatible with 2004 California emissions models.
What comes in the box?
One cylinder’s worth: piston, hardened wrist pin, retainers/clips, and piston rings.
How many kits do I need for a full engine?
Order six kits (one per cylinder) for a complete set.
What is the warranty?
Interstate-McBee provides a manufacturer warranty (commonly up to 24 months from installation). Ask us for the current policy applicable to piston kits.
Product Videos
Custom Field
YEAR 2003-2004
MAKE DODGE
ENGINE 5.9L
