My Uproar 60 is powered with a ST G-90-its not overwhelming-don't see why the 1.20 would not work-except you may have a balance problem with heavier 4 stroke-you can always build a hatch back towards fin area and move battery to tail section. Not sure about ground clearance for larger prop for 1.20, check that aspect before you go too far. I used some old landing gear from another plane, so there is a way around GC also-mine uses a 13/7, a 14/6 might work, but it would be close as I fly off grass. Great plane and loads of fun-let us know what you decide.