Hello all!

I have a Q50 tucked into my Miles reed Extra 260 with fiberglass 20in prop (heavy and flat and no pitch markings) The plane goes vertical, but has no speed. I need speed to fly patern aerobatics and the big bird currently flies like a slow stick. I was wondering if anyone has an 80in extra or equiv e/ a 50 on her. If so...... What prop do you recomend? A 20-10 or 22-8 or smaller. The engine is used and I was told it was a 50, but others said it was a Q52. How do I tell?

Thanks ahead of time for your help!