I have converted 4 different makes of 4 cycle gassers, 25 to 34cc..NONE would swing my 18-6 Mejzlik test prop within 1000 rpm of my bone stock G26....25cc four stroke torque is a myth....
Do a search, it's all here somewhere...
Closest was a Shindaiwa 34 with a bigger carb, 8000 rpm...1000 LESS than a G26...
A 64.9 Stihl backpack blower( I converted 4) runs about like a G62, maybe a little stronger..Same myth..