I've been flying a RCS 1.40 on a Hangar 9 Edge at 12 lbs RTF.
The motor is totally sweet....
The pitts muffler is very nice sounding, deep throaty, not whiny like the smaller two strokes.

I'm running three different brands of 16x8, and 17x8 props around 7500-8000 rpms and pulling the Edge around like it's meant to be..

I love being able to fly this size plane for less than 10 cents a flight and having the power to tractor through manuvers.

Honestly, the 1.40 is rated at about 15-16 lbs thrust...so a .60 size would be a TIGHT Fit!! and bring up your wing loading considerably. Now if your talking a 80 inch world models p-51 that would be sweet....with very light loading. Look for at least 1000 square inches of wing area to put this motor on.

Hope that helps.
CrazyHerb