In an effort to make the happy time a bit more quiet, I came up with this. An Arnold 1/2" B&S muffler with the threaded end cut down and 1/2" copper pipe brazed in. And some elbows and street elbows. It works! The sound is lower and the low end torque is higher. I can now run slower w/o the annoying "jerkyness". Rolling off the throttle coming to a stop is much smoother. I'm going to add another elbow and a reducer tomorrow and see how that works. Then I'll paint it all with the high temp grill paint and life will be good.