6.6L Duramax Race Exhaust Manifold - for LML LBZ LB7 Engines - Fits 2001-2016 Chevy Silverado GMC Sierra 2500HD 3500HD

SKU: XKV11201
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Description

This exhaust manifold kit is for LB7, LLY, LBZ, LMM, and LML engines. The manifold is made tough using high-quality ductile silica moly cast iron. The manifold ports are machined to match the factory gaskets to ensure the highest exhaust flow possible. 

Features

Fuel Economy Better Fuel Economy
Performance Quicker Spool Up and Lower EGT's
EGT Probe Port EGT Probe port pre-molded and tapped in each manifold for convenience
Color Gray
Material Cast Iron
Fuel Type Diesel
Mounting Style Bolt-On
Placement Placement on Vehicle: Left, Right

Fitment:

Vehicle Model Years Engine
Chevrolet Silverado 2500 HD 2001~2016 6.6L 
Chevrolet Silverado 3500 HD 2001~2016 6.6L 
GMC Sierra 2500 HD 2001~2016 6.6L
GMC Sierra 3500 HD 2001~2016 6.6L 

Note:

  • 2001-2004 6.6L LB7 Duramax
  • 2004.5-2005 6.6L LLY Duramax (RACE APPLICATION ONLY)
  • 2006-2007 6.6L LBZ Duramax (RACE APPLICATION ONLY)
  • 2007.5-2010 6.6L LMM Duramax (RACE APPLICATION ONLY)
  • 2011-2016 6.6L LML Duramax (RACE APPLICATION ONLY)

Note：These Exhaust Manifolds will NOT work with OEM up pipes.

Shipping & Return

SHIPPING & DELIVERY
Fast Processing & Reliable Transit

  • Processing: Orders are processed and shipped from the nearest available warehouse within 1 business day after payment.
  • Delivery: Estimated delivery time is approximately 3–4 business days after shipment.
  • Shipping - Free shipping on all orders within the contiguous 48 U.S. states.

RETURNS & EXCHANGES
30-Day Hassle-Free Policy

  • Return Window: We offer a 30-day return policy from the date of delivery.
  • Item Condition: Returned items should be unused, uninstalled, and in their original packaging when possible.
  • Return Process: To initiate a return or exchange, please contact our customer service team first to receive authorization and instructions.

WARRANTY
2-Year Limited Replacement Warranty

  • Duration: All products are backed by a 2-year limited warranty.
  • Coverage: This warranty covers manufacturing defects and product failures under normal use, and provides a replacement for qualified cases (repairs are not performed).

CUSTOMER SUPPORT
We’re Here to Help – Contact Us First

  • Priority Contact: For any order-related issues—including returns, warranty claims, or general inquiries—please contact us first before taking further action. We are committed to resolving your concern promptly.
  • Feedback Notice: If you are unsatisfied, we kindly ask that you allow us an opportunity to address the issue before leaving neutral or negative feedback.
  • Email Support: You can reach us at support@XKVracing.com.

What Does an Exhaust Header Actually Do?

The exhaust header is the first section of the exhaust system and mounts directly to the engine. Its role is to collect exhaust gases from each cylinder and route them into the rest of the exhaust system.

Compared to many factory manifolds, header designs often focus on smoother internal flow and more uniform exhaust routing before gases move downstream.

What You May Notice After Installation

Smoother exhaust flow as engine speed increases

More consistent engine behavior across the RPM range

Improved exhaust routing when paired with other intake or exhaust components

Changes in exhaust tone, depending on system configuration

When This Type of Upgrade Is Typically Considered

Addressing airflow limitations in the factory exhaust manifold

Planning coordinated intake or exhaust system updates

Replacing aging or restrictive original components

Build a balanced, performance-focused setup

Factory Manifold vs. Performance Header

Factory Exhaust Manifold

Designed to meet packaging, cost, and emissions requirements
Prioritizes durability and compliance across broad use cases

Performance Exhaust Header

Designed with exhaust flow characteristics in mind
Built for higher exhaust temperatures and specific vehicle platforms
Commonly used as part of an exhaust system configuration

FAST SHIPPING

Ships within 1 business day after payment
3–4 business day delivery

Secure and Reliable Checkout

Secure checkout with major payment options

LOCAL WAREHOUSE

Orders ship from U.S. warehouses when available

Easy Returns and Exchanges

30-day returns for eligible unused items

Parts Warranty

Warranty support for qualified manufacturing defects

Important Notice

Products on this site are intended for off-road, racing, or closed-course use where emissions laws apply. They are not represented as street legal, emissions-compliant, or legal for use on public roads unless explicitly stated.

Some products may remove, replace, relocate, disable, or alter emissions-related components, including but not limited to catalytic converters, EGR, DPF, SCR, DOC, O2 sensors, or related factory systems. Compatible tuning, calibration, or supporting modifications may be required to avoid engine codes or drivability issues.

Professional installation is recommended. Buyers are responsible for verifying product compatibility, local regulations, emissions requirements, and any required tuning or supporting modifications before purchase and installation.

Performance gains, sound changes, airflow improvements, temperature changes, fuel economy changes, fitment, and drivability results may vary. No specific performance gains are guaranteed.

Frequently Asked Questions

What do exhaust headers do? +

Exhaust headers help route exhaust gases away from the engine through individual tubes and collector-style routing. Actual results depend on the vehicle, engine condition, exhaust system, installation quality, and supporting components.

What's the difference between headers and factory manifolds? +

Factory manifolds are typically designed around packaging, durability, emissions requirements, and production cost. Headers or manifold-related exhaust upgrades may use different tube routing, flange designs, or connection layouts depending on the application.

Will headers increase horsepower? +

Headers may support improved exhaust flow where the product is compatible, but horsepower and torque changes are not guaranteed. Results vary by engine setup, tuning, exhaust configuration, vehicle condition, installation, and supporting modifications.

Do headers make the vehicle louder? +

Headers and related exhaust parts can change exhaust tone and may increase sound depending on the rest of the exhaust system. Final sound level depends on the engine, mufflers, catalytic converters, pipe routing, and complete exhaust setup.

Do I need tuning after installing headers? +

Tuning requirements depend on the vehicle, engine management system, O2 sensor setup, emissions equipment, and supporting modifications. Some installations may not require tuning, while modified builds may require professional inspection, calibration, or tuning to support proper drivability.

Are header products street legal? +

Header and exhaust products may be intended for off-road or racing use where emissions laws apply. They are not represented as street legal, emissions-compliant, or CARB-compliant for public road use unless a valid exemption is explicitly stated. Always check local regulations before purchase and installation.

Can I use headers with a stock exhaust system? +

Compatibility with a stock exhaust system depends on the vehicle and existing exhaust configuration. Some vehicles may require additional hardware, gaskets, connectors, adjustment, or fabrication to complete installation.

Are headers hard to install? +

Installation difficulty varies by vehicle. Tight engine bays, old hardware, rust, engine swaps, modified exhaust systems, sensor placement, and clearance around surrounding components can increase installation complexity. Professional installation is recommended.

Will headers affect reliability? +

Reliability depends on fitment accuracy, installation quality, vehicle condition, heat management, gasket sealing, fastener condition, sensor placement, and supporting components. Proper inspection and installation are important.