Go to Sears or look on Ebay. You can get a 42cc Sears (Poulan) or a true Poulan for less than $100.00. Sears has an area where they sell customer returns. Picked up a Sears saw with a 42cc engine for $70.00. Bought a hub, muffler, and CH ignition and have less than $280.00 invested. Turns a MA 18/8 at just over 8000 RPM on 50:1 Amsoil Dominator. My son fly's the engine in his SIG Extra 300 and it has incredible verticle pull. Good luck.