Smallplanes, I get my engines, carbs and parts from online stores like SEPW above. Between 170 and 190 for a short block. You can also get the smaller weedeater motors from Echo at these stores also. The hubs and such I make myself. I use CH igniotions in my conversions. If you take the cost of the ignition out you have around 250 in a 50cc motor. In my case I have an ignition for each motor but you could just swap the box between motors to save money. Not too shabby I would say. Here is a picture of my 44cc being setup in a Wildhare 1.20 size Edge for my son.