A stock dyna muffler is not a noisy beast. It is a little louder and has a deeper tone than the stock muffler. Also, you may not need to rejet with just a muffler change.

If you want a little more noise, you can drill a hole in the baffle plate that blocks direct access through the muffler. I put a 1/2 inch hole in mine and liked the resulting sound.

You are probably expecting the sound of a gutted dyna muffler. The baffle plate is a press fit into the muffler tube and can be knocked out with a hammer and a long rod or broomstick. If you do this, the muffler will be significantly louder, as the muffler becomes straight through with only perforations in the sides of the tube to modify the sound. If you make this mod, a rejet is in order. It may also lessen your midrange torque.

Hotrod ,Your need to rejet ,becomes greater as you move closer to sea level,If you drill the baffle ! (I wouldn't) I'd start with a1/4 inch hole and work up from there,keep in mind that a cone filter and a straight pipe (drilled baffle) is a setup that is very difficult to jet properly.