I have a ‘69 Z, factory setup 302, M20, 4.56, deluxe interior, 15” radials, and chambered exhaust. I’d probably say it’s a 5 out of 10 at 55-65 mph (though with these gears I don’t do a lot of long freeway cruising). It’s only at WOT / high RPM that it gets wake-the-neighbors / alert-the-authorities loud (9/10?). Not sure to your other questions.
I continue to be surprised how civil it is if you are civil with the loud pedal. It’s downright delightful at idle (even at 950 for the 302), and totally livable at cruise RPMs with windows down. At least to my younger ears I can’t imagine running a quieter system. I can barely hear the other Zs at cars & coffees, when standing next to them!
So +1 for chambered here. I think Eddie would be heard with the right sound system (maybe even through the single under-dash speaker)
