Muffler-can keep kinda quiet sounds off at rpm

AJ/FormS said
Don't forget that our A-bodies have natural tendency to create a resonance at between 55 and 60 mph that cannot be tuned out; and it's worse with the windows open. Don't believe it? just tow your car in that speedzone with the engine shut off.
If your engine rpm or exhaust system, excites that resonance, there ya go; instant drone. IMO, the fastback bodystyle is a lil better than big-trunk cars.

My 67 fastback was so loud with exhaust resonance that we couldn't talk while at cruise speed windows down or up. Tried two difference muffs and added resonators. Didn't help. Finally put the Helmholtz resonators on and the drone was gone, I could hear the wife no problem. Damn! :lol: