RE: Best engine for a 4*60
I maidened a guy's 4*60 with a Saito .91 in it and an MA 14 x 6 prop.
It was a very nice combination - not ballistic, but a really nice, well balanced low speed aerobat with a good flight time and a nice pleasant sound.
Like the other guys, I think the 4*60 is more of a four-stroke kind of aircraft than a two-stroke one.