Flowmaster 40 Series Chambered Muffler

40 Series Muffler - 2.50 Dual In / 3.00 Center Out - Aggressive Sound

PART# 425403

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$88.83   Suggested Retail
$71.96   Holleydays Price
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Universal Muffler - Not a direct fit. Some adaptation required


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.


  • Excellent Street/Strip and Off Road application
  • Noticeable interior resonance
  • Aggressive Sound Exterior Exhaust Tone
  • Durable fully welded 16 gauge aluminized steel


California Proposition 65 RequiredNo
Emission Code5
Inlet Connection TypeClamp
Inlet Diameter (in)2.5
Inlet PositionDual
Inlet Quantity2
MaterialAluminized Steel
Muffler Body Height/Thickness (in)4
Muffler Body Length (in)13
Muffler Body ShapeOval
Muffler Body Width (in)9.75
Muffler Inlet Diameter2.5
Muffler Outlet Diameter (in)3
Muffler Overall Length (in)19
Muffler SeriesOriginal 40 Series
Outlet Connection TypeClamp
Outlet Diameter (in)3.00
Outlet PositionCenter
Outlet Quantity1
Product TypeStreet Mufflers
Sound LevelAggressive Sound
Type of MufflerChambered
Part Number425403


This part is legal for sale or use on Emissions Controlled Vehicles, Uncontrolled (Non-Emissions Controlled) Vehicles, and Racing Use Only Vehicles because it does not affect vehicle emissions and is not covered by emissions regulations.

Tech Resources

Universal Muffler - Not a direct fit. Some adaptation required
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