The Dynomax Super Turbo Mufflers 17747 and listed as the quietest of the bunch?? I had the Ultra Flo SS polished on the '68 RR and really, really liked them. For what it's worth I currently have the Flowmaster chambered mufflers Series 40 on the '69 GTX and they are TOO LOUD and they have it terrible, terrible resonance right at normal cruising speed (4-speed/3.54) and my wife can't stand it....I guess that's why I haven't changed them to the Dynomax Ultra Flo SS that are new and sitting on the shelf wink drumhit. IMO you might like the Ultra Flo welded as they are even louder than the Ultra Flo SS and for sure louder than the Super Turbo's.

One thing I can't understand is why the "welded" Ultra Flo (bottom or last image) is listed as "louder" than the, what looks to be the same internal design, Ultra Flo SS polished muffler (first muffler image)??

#1 muffler image = Ultra Flo SS Polished

#2 muffler image = Super Turbo 17747

#3 muffler image = Ultra Flo Welded

Mike



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