Flowmaster sound guideline

40 Series Mufflers
Deep powerful sound outside of the vehicle, interior
resonance in most all applications at different
R.P.M. levels.
Recommendations:
Generally used on early and late-model street/strip
vehicles with or without catalytic converters seeking
a more aggressive tone. An H-Pipe is strongly
recommended in all dual exhaust systems.

50 Series Mufflers
Mellow yet powerful sound in most applications.
Quieter than 40 Series mufflers outside. A special
"Tuning Chamber" helps reduce interior resonance
at most driving speeds.
Recommendations:
Most all street/strip applications with or without
catalytic converters. Off-Road/Race applications.
An H-Pipe is strongly recommended in all dual
exhaust systems.

30 Series Mufflers
Mellow yet powerful tone. The sound level is a little
quieter than the "50 Series" outside of the vehicle,
but with more of that "original Flowmaster sound."
The combination of added case volume and the
unique "volume chamber" creates a larger low
pressure area behind the chamber than a "50
Series" muffler. This leads to better scavenging of
exhaust gases, and a sound that is exclusive to the
"30 Series" muffler.
Recommendations:
For use on all high performance street/strip
applications. Use on Late Model Trucks with single
exhaust and catalytic converters that prefer more
tone, or trucks with dual exhaust. An H-Pipe is
strongly recommended in all dual exhaust systems.

Big Block Series Mufflers
Mellow tone. Increased volume of case size and a
specially developed "Tuning Chamber" makes this
the quietest muffles in the Flowmaster Line, both
inside the vehicle, and outside the vehicle.
Recommendations:
For use on all high performance street vehicles,
Chevy/GMC Suburbans, Tahoes, Yukons, trucks
used as tow vehicles, and most all Motorhome/R.V.
applications. An H-Pipe is strongly recommended
in all dual exhaust systems.