I use stock mufflers on my 68 Coronet. Years ago I used glasspacks, turbo mufflers, etc.
The mufflers that I used are the MSL mufflers. AP Exhaust makes them. They sound great. It's a stock muffler. It's not a performance muffler. It gives a period correct exhaust sound. And they are not loud at all. Very happy with them.
http://www.apexhaust.com/automotive-light-truck-2/overview/

I just replaced the mufflers and pipes on my 91 Crown Vic police car. I used the Walker Sound FX mufflers. The car is a factory dual exhaust with h-pipe. These are very quiet too. Very happy with these too. Someone else mentioned about these mufflers on this thread.
Give these mufflers a try. I would try the MSL's first.
I think you will like them.