I did a couple 26cc from blowers. These have 4-bolts on the backplate and the muffler is secured with screws. I set them up for Rcexl igntions and installed a larger 2-screw carbs. These engines also have the advantage of having a long shaft so the prop hub is easier. I traded one to a guy from my club for a G-38 with a bent crank. He installed it in a BUSA biplane, http://shop.balsausa.com/product_p/449.htm. He is very happy with it. That biplane is for the .60 to 1.08 range of glow engines. These are not powerhouse engines. But, in the right application they work out OK. They are not high quality. They were cheap, the blowers were cleared out at about $30 so I bought several. I have not messed with the newer 2-screw type so, I have no feedback on those.