I think this is as good of a thread as any to ask this question- I have a 1/4 scale cub with an RCS 1.40 that I'm really tired of futzing with. I'd like to replace it with something in the 20-26cc gas range that is RELIABLE, but I also don't want to cut the cowl up (any more that it already is - just a slot in the bottom for the plug cap). The biggest problem appears to be the width, especially on the on muffler side (critical measurement from the propshaft center to the outside edge of the muffler). The current engine has a wrap-around muffler for inverted mounting. It appears to me the only options are the extinct Roto 25 and the Evo 26GT/GX. Am I missing any option here? Anyone familar with the standard inverted RCS 1.40 dimensions who can comment on replacements?