21-26 Ford F-150 2.7L/3.5L/5.0L Flowmaster 818171 Outlaw Direct Fit Muffler

Flowmaster Outlaw Direct Fit Muffler – Part Number 818171

The Flowmaster Outlaw Direct Fit Muffler for the 2021-2026 Ford F-150 delivers an aggressive exhaust note and performance-focused design without requiring a complete exhaust replacement. Designed for 2.7L, 3.5L, and 5.0L non-PowerBoost engines equipped with factory dual tailpipes, this direct-fit system replaces only the factory muffler and over-axle pipes while reusing the factory dual tailpipes and tips. Durable 409 stainless steel construction, 3.00-inch mandrel-bent tubing, and a Flowmaster Outlaw Series muffler provide a performance-oriented exhaust upgrade with optimized exhaust gas flow. Dyno testing showed gains of up to 16 horsepower and 21 lb-ft at the rear wheels, making this system an attractive choice for F-150 owners seeking a more aggressive sound and performance-focused exhaust setup.

Key Features

• Designed for 2021-2026 Ford F-150 models with 2.7L, 3.5L, and 5.0L non-PowerBoost engines.
• Fits trucks equipped with factory dual tailpipes.
• Flowmaster Outlaw Series chambered muffler delivers an aggressive exhaust sound.
• 3.00-inch mandrel-bent pipes support efficient exhaust gas flow.
• Constructed from durable 409 stainless steel throughout.
• Replaces the factory muffler and over-axle pipes only.
• Reuses the factory dual tailpipes and tips.
• Uses existing factory hangers for a direct-fit installation.
• Includes clamps, hangers, installation instructions, and necessary installation hardware.
• Dyno-tested performance gains of up to 16 horsepower and 21 lb-ft at the rear wheels.

Benefits

• Provides an aggressive exhaust note for a more performance-oriented F-150 sound.
• Offers a direct-fit upgrade without replacing the factory dual tailpipes and tips.
• 3.00-inch mandrel-bent tubing promotes strong exhaust flow and performance.
• 409 stainless steel construction provides durable exhaust-system performance.
• Factory hanger compatibility helps simplify installation.
• Performance testing demonstrated gains of up to 16 horsepower and 21 lb-ft at the rear wheels.
• Backed by Flowmaster's Lifetime Limited Warranty for added ownership confidence.

Product Specifications

• Part Number: 818171
• Brand: Flowmaster
• Product Type: Exhaust System
• Part Type: Exhaust Muffler Assembly
• System Type: Direct-Fit Muffler
• Exhaust Series: Outlaw
• Muffler Series: 10 Series
• Muffler Type: Chambered
• Muffler Shape: Oval
• Sound Level: Aggressive
• Material: 409 Stainless Steel
• Pipe and Tubing Material: 409 Stainless Steel
• Main Piping Diameter: 3.00 inches
• Tubing Diameter: 3.00 inches
• Muffler Inlet Diameter: 3.00 inches
• Muffler Outlet Diameter: 3.00 inches
• Inlet Quantity: 1
• Outlet Quantity: 2
• Outlet Configuration: Dual
• Inlet Location: Center
• Muffler Inlet Location: Center
• Muffler Outlet Location: Dual
• Inlet Type: Slip-Fit
• Outlet Type: Slip-Fit
• Mount Type: Uses Factory Hangers
• Body Height: 4.00 inches
• Body Width: 9.50 inches
• Body Length: 6.50 inches
• Muffler Overall Length: 12.20 inches
• Overall System Length: 55.20 inches
• Muffler Material: 409 Stainless Steel
• Muffler Color: Black
• Muffler Finish: Black High-Temperature Paint Finish
• System Finish: High-Temperature Paint
• Clamping Type: Flat Band
• Clamps Included: Yes
• Hangers Included: Yes
• Exhaust Tips: Not Included; reuses factory tips
• Heat Shield Attached: No
• Gasket or Seal Included: No
• Spring Bolt Kit Included: No
• Emissions Code: 5
• California Proposition 65 Required: Yes
• California Proposition 65 Chemicals: Chromium (hexavalent compounds) and Nickel (metallic)
• UPC: 090127846599

Install Difficulty level

Easy. The direct-fit design replaces the factory muffler and over-axle pipes while reusing the factory dual tailpipes, tips, and factory hangers. Installation instructions and the necessary hardware are included, making this a straightforward upgrade for a properly equipped home garage. Installation can take approximately 45 minutes.

Vehicle Fitment

2021-2026 Ford F-150

• Make: Ford
• Model: F-150
• Engine: 2.7L, 3.5L, or 5.0L
• Engine Configuration: Standard non-PowerBoost
• Exhaust Configuration: Factory dual tailpipes
• Factory Exhaust Requirement: Originally produced with optional dual exhaust exiting through the rear bumper
• Does Not Fit: PowerBoost hybrid models
• Does Not Fit: Models originally produced with single-side-exit exhaust
• Does Not Fit: Models with the OEM active exhaust option

For questions about this product or to report product description inaccuracies, contact the MPT Performance experts at (407) 636-7077 or by email.