I ran the 3" in & out Hooker Aero Chambers in my "68 A-Body running a 408 Magnum with a full 3" TTI and found them too loud. I swapped them to the Dynomax's I was running in my 493" RB with full 3" TTI in my E-Body and visa versa.
The Aero Chambers were then significantly quieter but still ever so slightly louder than the Dynomax's in the big block car and the Dynomax's were just right in the A-Body small block car.
On a side note: A buddy of mine has a 400" B motor in his car. He added about a 2.5 foot section of same sized exhaust pipe that was "J" shaped a few feet after his collectors on both banks. It somehow cushioned the exhaust pulses enough to eliminate his drone. There is a name for this technique, but I don't remember what it's called.
Exhaust sounds are actually pretty complex and tuneable. Much like musical instruments with regard to sound. I found that using an ovalized exhaust tip "sweetens" the sound of the exhaust to the human ear. I even use them on my cut-outs with the same effect as the flared ends of musical instruments.