Quiet muffler choices

Your 372, is a hot build up?
I’m not sure what you’d looking for. The Quietest muffler, the muffler case should be as long as possible to Absorb the most sound. This however can lead to less than optimum power output.
These were super quite.
Cut away of a Dyno Max muffler #18381

Also, click on the links within that thread.