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Flowmaster 425403 40 Series Chambered Muffler

Free shipping on orders over $29.99

$92.55

$ 42 .99 $42.99

In Stock

About this item

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


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.


Phillip siljander
Reviewed in the United States on January 2, 2024
I like the tone that resonates from the muffler and I like the welded construction.
Jonathan
Reviewed in the United States on January 12, 2024
sounds perfect in my v8
Bailey Smith
Reviewed in the United States on December 19, 2023
Great muffler!!!! Helped make my V6 nissan motor with long tube headers sound better and louder
me
Reviewed in the United States on November 10, 2022
It is pretty loud in the cab between 1700 and 2000 rpm. Quiet enough when cruising over 60mph. Nice deep tone with no crackle or snap. It is shorter and the inlets are wider than the factory muffler, so a short length of shaped pipe is needed to be welded in to compensate. But overall it looks good and sounds good.
Brent Lyons
Reviewed in Canada on February 7, 2021
Flowmaster master is as dependable as any brand you can name. You buy it for one reason, that sound. The fact that it’s quality built to last and great value are the bonus. Swapped out the dual 2.5” in by single 3” out 50 series for the same configuration but a 40 series! It my truck sounds so nice and deep now but not too loud still at idle. Great engineering!
Dario J
Reviewed in the United States on February 22, 2021
Sounds great on my 5.7 Tundra
SL
Reviewed in the United States on August 5, 2020
Nice deep tone. Great construction. Only been on for a few miles and a few months but no signs of corrosion. Application: 98 5.7 K2500 GMC. Side note: stock pipes are just a little spread out for this muffler so you will need to get creative. It will not just slide on. If you’re coming from stock exhaust you will be pleased. If you’re coming from straight pipes you’ll wonder where all the sound is, but will notice a positive difference otherwise.
Austin
Reviewed in the United States on September 20, 2019
This is a great double 2.5 inlet and a single 3" outlet. Previous experience led me to buy this an it is great for my SS Suburban. You can tell it's a big block Chevy now 🤣!
Jared V.
Reviewed in the United States on November 12, 2019
Flowmast always has had great products! The 40 series always had the aggresive sound. Worked well on my 96 dodge. Made the v10 sound a little meaner
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