Hello!
It's all about weight!
Light airplanes fly better and a ordinary warbird with a 160cm wing span weighting around 4-4,5kg will fly just fine on a 10cc (.61) twostroke, at least if you fly at sea-level.
Use a 12x6 or 13x5 APC prop and your plan will perform very good.
I have a MVVS 15cc two stroke in my Great Planes GEE BEE R-2 (weigh 5kg) and it has very good performance.

Regards!
Jan K
Sweden