Ok, i get it, it's a prop plane, thats cool,

But, you still should not have that much vibration. If your prop/spinner are perfectly balanced, and the engine is presumably factory balanced, then you might be overreving the engine. You could experement with more pitch and or diameter to lower your RPM. Concentrate on lowering your vibration levels. Because, even if you do get your fuel to stop foaming with padding or some other bandaid, your electronics will be the next thing to fail, and it won't take long.