aFe Large Bore-HD Cat-Back Exhaust System

2003–2004 Dodge Ram 2500 / Ram 3500 5.9L Cummins

Part #: 49-42005

Overview

The aFe Large Bore-HD Cat-Back Exhaust System is a precision-engineered upgrade designed specifically for 2003 to 2004 Dodge Ram 2500 and Ram 3500 trucks equipped with the 5.9L Cummins engine. This cat-back system enhances exhaust flow, resulting in improved horsepower and torque while delivering a more aggressive exhaust tone that complements the truck’s powerful diesel engine.

Built for truck owners who demand both performance and durability, this exhaust system helps reduce exhaust gas temperatures, contributing to better engine efficiency and longevity. Whether you’re towing heavy loads or seeking a more commanding sound and improved throttle response, the Large Bore-HD Cat-Back is a reliable and effective solution.

Key Features

Combining advanced engineering with high-quality materials, the aFe Large Bore-HD Cat-Back Exhaust System offers:

• 4-inch mandrel-bent 409 stainless steel tubing for maximum exhaust flow and corrosion resistance
• High-flow, straight-through perforated muffler measuring 8" diameter by 30" length for an aggressive yet refined exhaust note
• Muffler delete pipe included for those who prefer an even louder and more aggressive sound
• Polished stainless steel exhaust tip for a clean, professional appearance
• Bayonet-style hangers with swaged ends for secure, factory-style mounting and easy installation
• Slotted and swedged pipe ends paired with premium band clamps to ensure a tight, leak-free seal
• Flow bench and dynamometer tested for optimal pipe sizing and muffler design
• Made in the USA with a 2-year limited warranty for peace of mind

Construction & Design

This cat-back exhaust system is crafted from durable 409 stainless steel, known for its excellent corrosion resistance and long-lasting strength, ideal for harsh road and weather conditions. Each pipe is mandrel bent to maintain a consistent diameter throughout bends, eliminating flow restrictions caused by crushed or kinked tubing. This ensures smooth, unrestricted exhaust flow, which is critical for maximizing engine performance and efficiency.

The system features fully welded hangers on both sides with swaged bayonet ends that lock securely into the factory mounting points, providing a stable and rattle-free installation. The two-piece tailpipe design allows for precise adjustment during installation, ensuring a perfect fit on your Dodge Ram 2500 or 3500.

Performance & Sound

The aFe Large Bore-HD Cat-Back Exhaust System increases exhaust flow by up to 29%, which helps reduce exhaust gas temperatures by as much as 100 degrees. Lower EGTs contribute to improved engine efficiency, power output, and component longevity. The included muffler delivers a deep, aggressive exhaust tone that enhances the driving experience without being overly harsh or droning. For enthusiasts seeking maximum volume and flow, the muffler delete pipe option provides an even more commanding and aggressive exhaust sound.

Installation & Fitment

Designed as a direct bolt-on upgrade for 2003–2004 Dodge Ram 2500 and Ram 3500 trucks with the 5.9L Cummins engine, this cat-back exhaust system installs using factory mounting locations without the need for cutting or welding. The included detailed instructions, premium band clamps, and bayonet-style hangers simplify installation, ensuring a secure, leak-free fit. The modular tailpipe design allows for fine-tuning during installation to achieve the perfect alignment and fitment.

What's Included

• 4-inch mandrel-bent 409 stainless steel tubing
• 8" diameter by 30" length straight-through perforated muffler
• Muffler delete pipe for aggressive sound option
• Polished stainless steel exhaust tip
• Premium band clamps
• Bayonet-style hangers with swaged ends
• Detailed installation instructions

Ideal For

This exhaust system is ideal for Dodge Ram 2500 and 3500 owners from model years 2003 to 2004 who want to enhance their truck’s power, torque, and exhaust sound. It is especially suited for those who tow or haul heavy loads and require a durable, high-flow exhaust solution capable of withstanding demanding conditions. Enthusiasts seeking a bold, aggressive exhaust note combined with reliable performance gains will find this upgrade an excellent choice.

aFe POWER (Advanced FLOW Engineering) offers dyno-proven intake, filtration, and exhaust upgrades aimed at measurable performance gains. The brand’s lineup is geared toward enthusiasts looking for better airflow, improved sound, and durable materials—from cold air intakes to stainless exhaust systems for street and track applications.