"Jay Honeck" wrote

Our friend has an airplane powered by an unmuffled Chevy V-8, and it
sounds just as sputtery at idle...

Most high HP V-8's do sound sputtery, due to a high lift cam with more than
usual valve open overlap.

Even then, V-8's with a stock cam often sound rough at idle, even with a
muffler, if idle is set relatively low. How about Harley's? They all sound
rough, with or without mufflers.
--
Jim in NC