The new Flowmasters I installed on my Edelbrock s/c 2010 GT sound great at idle and cruising, but terrible between 2500 and 3000 RPM. Any ideas or comments/similar experiences?

 

Define "terrible". Is it droning? NOT loud enough?

 

The "terrible" is a vibratory noise. It gets loud at 2500, then dissipates. It almost sounds like body panels vibrating on a car with the base pumped up.

 

I meant bass.

 

Sounds like drone!

I have the flowmaster American thunder on my 08 and it drones quite a bit...
But, I love the sound of it!

I did notice that when I replaced my clutch and flywheel 2 weeks ago, its
not as bad. Perhaps the excess load from a slipping clutch was the culprit.

 

yep, the louder Flowmasters drone. I had these on my 2010 GT and they didn't drone much at all. On my 2012 I have this kit, and they're much louder and droning.