Flowmaster 2.50 IN(D)/OUT(D) 40 Series Muffler

The Original 40 series muffler delivers an aggressive exterior and interior tone. If you're looking for that original Flowmaster sound this is the muffler is for you. Constructed of 16 gauge aluminized steel and fully MIG welded for maximum durability. 40 Series - 2.50" IN(D)/OUT(D) - Aggressive Sound Universal Muffler - Some adaptation may be required.

• Excellent Street/Strip and Off Road application
• Durable fully welded 16 gauge aluminized steel
• Aggressive Sound Exterior Exhaust Tone
• No internal packing to blowout

The Flowmaster 40 Series muffler delivers the aggressive exterior and interior exhaust tone associated with the original Flowmaster sound. Designed for drivers seeking a bold street, strip, or off-road exhaust note, this universal muffler provides a durable performance-oriented solution for a variety of custom exhaust applications. The Flowmaster 425404 features a 2.5-inch inlet and outlet configuration and may require adaptation for installation depending on the vehicle and exhaust system.
Constructed from durable 16-gauge aluminized steel, the muffler is fully MIG welded to support long-term strength and dependable performance. Its internal design does not use packing, helping eliminate concerns about packing material blowing out over time and maintaining a consistent sound profile. The rugged construction makes this muffler well suited for demanding automotive applications where durability and an aggressive exhaust character are important.
The Flowmaster 425404 40 Series universal muffler is an excellent choice for street and strip vehicles, off-road builds, and custom exhaust projects. Verify inlet and outlet positioning, vehicle clearance, and required exhaust adaptations before installation. Professional installation is recommended to ensure proper fitment, alignment, and leak-free performance.

Features:

• Aggressive Sound: Produces a bold exterior and interior exhaust tone with the original Flowmaster 40 Series sound.

• Universal Fit: Designed for custom exhaust applications; some adaptation may be required for installation.

• Durable Construction: Made from 16-gauge aluminized steel for dependable strength and corrosion resistance.

• Fully MIG Welded: Welded construction supports long-lasting durability under demanding driving conditions.

• Packing-Free Design: No internal packing to blow out, helping maintain a consistent exhaust tone.

• Versatile Application: Suitable for street, strip, and off-road automotive applications.