GM Duramax LMM Downpipe Back Exhaust (2007.5-2010)
Type: Exhaust Systems
Unleash raw performance and sound for your 6.6L Duramax. Engineered for 2007.5–2010 Chevrolet Silverado and GMC Sierra 2500/3500HD models, this downpipe-back exhaust delivers maximum flow, lower EGTs, and an aggressive exhaust tone that commands attention. Available in 4” and 5” T409 stainless options.
Upgrade your LMM Duramax with a precision-built downpipe-back system designed for off-road power and reliability. Featuring mandrel-bent 16-gauge stainless tubing, Contour Bent Hangers, and stainless band clamps, this system offers excellent durability and straightforward bolt-on installation.
Vehicle Fitment
- Compatible: 2007.5–2010 Chevrolet Silverado 2500HD / 3500HD 6.6L Duramax LMM
- Compatible: 2007.5–2010 GMC Sierra 2500HD / 3500HD 6.6L Duramax LMM
- Cab/Box: EC–CC / SB–LB / Dually
- Excludes: Cab & Chassis models; 3-bolt flange systems
Specifications
| Material | 16-gauge T409 stainless steel |
| Diameter | 4” or 5” mandrel-bent tubing |
| Configuration | Downpipe-back, single outlet |
| Clamps | Stainless steel band clamps |
| Finish | Natural brushed stainless |
| Use | Off-road and race applications only |
What’s Included
- Downpipe-back exhaust assembly
- Pre-welded Contour Bent Hangers
- Stainless steel band clamps
- All required mounting hardware
- Optional muffler add-on (for quieter operation)
Key Features
- High-flow, performance downpipe-back design for maximum exhaust velocity
- Lowers EGTs and reduces backpressure under load and towing
- Durable T409 stainless resists heat, corrosion, and fatigue
- Contour Bent Hangers for precise, rattle-free alignment
- Leak-free stainless band clamps
- Straightforward bolt-on install—no cutting or welding required
Benefits
- Noticeable gains in throttle response and overall performance
- Deep, powerful exhaust tone ideal for off-road builds
- Built for high-heat, high-vibration diesel use
Frequently Asked Questions
Is this exhaust street-legal?
No. It is for off-road or race use only and not legal on public highways.
What’s the difference between the 4” and 5” versions?
The 4” system provides excellent fitment and a moderate tone, while the 5” offers a deeper, more aggressive sound and maximum exhaust flow.
Does the kit include all hardware?
Yes. Every system includes stainless band clamps, pre-welded Contour Bent Hangers, and all required mounting hardware for installation.
Do I need tuning after installation?
Yes. Proper race tuning is required for safe operation and optimal performance results.
Will this exhaust lower EGTs?
Absolutely. The free-flowing design reduces backpressure and helps lower exhaust gas temperatures under heavy load or towing conditions.
Important Notes:
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Important Notices
- Off‑Road Use Only
Products sold by JS Speed are intended for off‑road use and may be illegal on public roads where emissions or pollution‑control laws apply. - Check Local Laws
Before purchasing or installing, verify all applicable local, state/provincial, and federal regulations to ensure the modification is legal in your area. - Professional Installation Recommended
These parts should be installed by qualified professional mechanics. Improper installation can cause performance issues or vehicle damage. Unless a product page explicitly states otherwise, installation instructions are not included. Components are designed for users with solid mechanical knowledge, and minor adjustments or modifications may be required for proper fitment. Returns or refunds cannot be accepted due to difficulty completing an installation or the absence of instructions. - Warranty Impact
Use of these parts may void your vehicle’s factory warranty. Confirm with your vehicle manufacturer before purchase and installation. - Limitation of Liability
JS Speed is not responsible for damage, failures, or issues arising from the use or installation of these products. - Product Images
Images are for illustration only and may differ from the actual product due to manufacturer updates or improvements. - No Performance Guarantees
While these products are designed to enhance performance, JS Speed does not guarantee specific performance results.
