i run 3/8 on my 660. 3/8" on my race saws.. 404 will make a larger kerf, take a bit more HP to run, but yes it is the extreme duty way to go. when i used to mill with my old husky 288 3/8 did just fine, and i pushed it pretty hard. my old 026 race saw was turning 19,500 RPM with tuned pipe and...