Product Description
DIAMOND EYE K4120A is a 4.0" aluminized steel cat-back exhaust system with single passenger-side exit and performance muffler for 2004–2005 Chevy/GMC Silverado/Sierra 2500/3500 6.6L LLY. Mandrel-bent tubing reduces backpressure, improves throttle response, and adds a deeper, towing-friendly tone.
FAQ: WILL THIS FIT MY LLY?
Yes—this kit is designed specifically for the 2004–2005 LLY Duramax 2500/3500 (all cab/bed lengths). Always verify your model year and emissions equipment before ordering.
FAQ: IS TUNING REQUIRED?
No tuning is required for a cat-back install. It bolts to the factory location and retains the catalytic converter.
FAQ: WHAT’S INCLUDED?
System components, performance muffler, clamps, and passenger-side tailpipe. Tips and adapters are sold separately unless noted.
Fitment Details
- Vehicle: 2004–2005 Chevrolet Silverado/GMC Sierra 2500HD & 3500HD
- Engine: 6.6L Duramax LLY
- Configuration: 4" cat-back, single side exit (passenger side) with muffler
Cross-Reference / Alternatives (MBRP-only)
- MBRP S6000AL 4" Armor Lite Cat-Back (2001–2005 LB7/LLY)
- MBRP GMAL413 Regular Cab Adapter (when required)
Specifications
| Brand | Diamond Eye Performance |
|---|---|
| MPN | K4120A |
| UPC | 841963121421 |
| GTIN | 0841963121421 (UPC-A) |
| Material | Aluminized steel |
| Main Tube Diameter | 4.0" |
| Exit | Single side (passenger) |
| Sound Level | Moderate, towing-friendly |
| Shipping Weight | ~77 lb |
| Package Dimensions | 52" x 21" x 13" |
| Prop 65 | WARNING: Cancer and Reproductive Harm — www.P65Warnings.ca.gov |
