I have discovered the mower shop next door has several Stihl 27cc and 25cc engines just laying around... they use them for parts, but most of the parts are not taken from the engine just the trimmer.... Guy said he would sell me 10 of them for $100... Has anyone converted these engines for RC? The have rear exhaust porting, is this a problem? I have a feeling I'll need to fabricate the muffler, but that's not a problem... Is this a good deal? I don't see much info. on Stihl engines.