10cc's isn't much. But you have to consider other changes like axle size, spacers, brakes and matching sprocket (matching wheel design), maybe fender clearance with the low profile over your old style.
Lots of threads on here of member trying to put a 260 on a 250 and a 250 on a 240. Search them out!
On the belt side your only talking 5cc's so you could let that rub out without harm I would think if it doesn't clear.
Going to be a costly experiment though if it's doesn't work. You probably won't find anyone here that has tried it with your limited model but you never know.
Oh, have you measured how much space you have between the belt and tire?
