I read a lot of posts where people are changing mufflers because they are too loud. I have Flowmaster 40's , I don't mind the loudness but would like to reduce the inside noise( resonance).Looking for ideas that worked for some of you. If there is anything that works. Thanks, John

I recently swapped out my Flowmaster 40's for a pair of Magnaflows - same size case. I ended up with PN 11226 stainless 14" x 4" x 9".

I really like the sound, I was concerned they would be too quiet, they're not.

I have a Magnaflow 3" system w an x-pipe and turndowns right off the mufflers. It is pretty rowdy sounding at idle and there is some resonance but at highway cruise speeds(around 2500rpm in 5th gear) I find it quite acceptable with no resonance. I had the tailpipes which dump behind the rear tire and it was much better at idle but I can't fit them in anymore with the Alston G-Bar 4 link setup I have now. The Magnaflow mufflers give a completely different sound that Flowmasters, I get complements all the time on how it sounds.

Not your case but in mine, I run the 80 series Flowmaster transverse and it was loud, I set two 3" flow through bullet glass packs to act as resonators, That did the trick. I placed them about the same place you have those 40's, under the seat.

I had a flowmaster "American Thunder" system with h-pipe on my other car. Switched it out to a Pypes 3" stainless system, car has much less cabin resonance and actually picked up a few hundredths at the track.

Tail Pipes must be out the Back. A Mechanical Distributor without Vacuum Advance will cause the Exhaust to Drone at cruise.

Tail Pipes must be out the Back. A Mechanical Distributor without Vacuum Advance will cause the Exhaust to Drone at cruise.


Never heard this, is it due to vacumn changes in engine loads and timing changes? Never thought about this. Yes, I do understand the pipes out back.