1/5 scale Waco ARF 63" wing 15cc gas
 

I have a couple questions about this plane, 1 it says a 15cc gas. I would like to know the largest cc gas anybody has put on it and it fit the cowling ? And, is it possible to get a twin cyl to fit the cowling ? Especially since, oh say a 20cc twin, has such a large carb on the top and not in front. Any ideas ? Thanks very much.