It depends on what mood I'm in. Sometimes I like the sound of an engine, sometimes not.
Besides, I'f I'm not burning gas, checking engine oil, etc ... I don't feel I've accomplished as much in the yard. The oversized-desk-fan-on-its-face concept probably works well, but you won't see me with one anytime soon.
Yeah, however exhaust attaches to this engine, you would have to start there and build/adapt a flange and then fabricate the steel tubing yourself to accept the muffler. I'm talking proper tube bending and careful welding. Not an easy thing to do. I know I don't have the tools.
I'd be sure to have at least one 90 degree bend to help cancel out the noise.
Plus "Muffzilla" (even the smallest aftermarket automotive mufflers are gonna be massive) is gonna need an extra bracket or two attached to the deck to hold it in place.
Forget the long and skinny mufflers designed for ricers.
You want something shaped like a swollen football ... fat is phat.
--- Bror Jace