all the homlite saws at home depot are great canidates.
the smallest one is a 33cc. the mag is attached to the motor, and you can mount it like a glow engine.
They also have a 42cc saw...but if you look on the actual saw, the little sticker that tells you the displaement actually says 46cc!!
then they have 46cc saw. all the motors have the mag attached to the cyl and are ez to convert and make good power.
good luck!!