A friend of mine is doing rc tractor pulling (http://www.micropulling.nl/micropulling/). They have got a class up to 10cc (.60 cu in.) engines. He is currently running a CMB45 45 RS evo. However he would like to increase the size of the engine to get (as close as possible) to 0.60. Would that be possible with this engine (Bore out the sleeve and get a bigger piston)?. Or would it be possible to use a CMB67 and down size it (don't know how?). Who got do this job? Thanks for your input.