I converted a concret saw a while back.

It was a 70cc engine that is just a power house.

Concret saws have great filters on them, my cylinder and piston looked like new.

Forged crank, rod and piston. Yours should be the same.

Mine is a Partners saw, made in Sweden.

Stihl makes top line stuff, especially their commercial line.

http://www.rcuvideos.com/video/72cc3holeMuffler-wmv