When I was a teenager many years ago I found out by accident that when coasting down hill when the ignition switch malfunctions, kaboom. After several times the muffler blew apart, man that was loud and obnoxious. Dad give me a round heavy duty truck muffler, cut the old muffler out and welded the new heavy duty muffler in its place. It was a little louder than the original muffler, didn’t sound like an A, couldn’t make it kaboom again.