Product Description
DIAMOND EYE K4120S-RP is a 4.0" 409 stainless cat-back, single side exit system for 2004–2005 Chevy/GMC 2500/3500 6.6L LLY Duramax (all cab/bed). It deletes the muffler for maximum flow and an assertive tone while retaining a bolt-on, emissions-era cat-back layout.
FAQ: WILL THIS FIT MY LLY?
Yes—this kit is designed for 2004–2005 LLY Duramax 2500/3500 trucks (all cab/bed). Always confirm model year and engine (LLY) before ordering.
FAQ: WHAT MATERIAL IS IT?
409 stainless steel tubing and hardware for long-term durability in harsh climates.
FAQ: DOES IT REQUIRE TUNING?
No tuning is required for a cat-back install. Reuse factory hangers and follow torque sequence.
Fitment Details
- Vehicle: 2004–2005 Chevrolet Silverado / GMC Sierra 2500HD & 3500HD
- Engine: 6.6L Duramax LLY
- Configuration: 4" cat-back, single passenger-side exit, no muffler
- Material: 409 stainless steel
Cross-Reference / Alternatives (MBRP-only)
- MBRP S6000AL — 4" Armor Lite (aluminized) cat-back for 2001–2005 LB7/LLY.
- MBRP GMAL413 — regular-cab adapter often used with 01–05 cat-back systems.
Specifications
| Brand | Diamond Eye Performance |
|---|---|
| MPN | K4120S-RP |
| UPC | 841963121452 |
| GTIN | 0841963121452 (UPC-A) |
| Material | 409 Stainless Steel |
| Tubing Size | 4.0" |
| Exit | Single, passenger side |
| Includes | Cat-back tubing, clamps/hardware (no muffler) |
| Shipping Weight | ~71–77 lb (package) |
| Package Dimensions | 52" x 21" x 13" |
| Prop 65 | WARNING: Cancer and Reproductive Harm — www.P65Warnings.ca.gov |
