2003.5-2007 Powerstroke 4" Turbo Back Exhaust - No Muffler (421025 / 422021)

The 421025 / 422021is a 4" turbo-back exhaust system for the 2003.5-2007 Ford F-Series. It replaces your restrictive OE exhaust system with a 4" mandrel-bent straight pipe exhaust system, this kit has no muffler and is intended for race applications. Just like all of Flo-Pro Manufacturings Exhaust kits, it will come with all the required clamps, pre-weld contour bent hangers, and stronger flanges to help you sail through the installation process. This system not only sounds great but also improves torque, mileage, and throttle response!

Part Number: 421025 / 422021

• 4" Turboback Single Exhaust system.
• No Muffler
• Aluminized Steel & Stainless Steel Options
• Single Side Exit
• Easy Install - Mounts to OE Hangers

Aluminized steel is the budget-friendly choice. It has a protective coating that holds up well, but once that coating wears it will eventually rust through, especially in salted winter climates. The stainless option is T409 stainless, an automotive-grade steel built to resist rot, and it will typically outlast the truck. T409 is not polished show-grade stainless, so light surface rust or discoloration can still show up over time. That is cosmetic only and won't affect performance or service life.

• This system will NOT fit trucks with a Manual Transmission

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• ?

  Does this kit dump in front of or behind the rear axle ?

  Exits behind the rear axle, single-side exit, passenger side after the rear tire.