Try the APC 14x6 prop it will pull harder than the MAS prop. I have tried both and the APC is better. I don't think that you will get the RPM that you need with the 14x8 prop. If you want more speed use the 13x8 prop it will turn more RPM and will make your extra haul. You can aslo use the MAS 14x7 scimitar prop they work good also. A lot or guys at my field are using the TT 91's for warbird racing and using the 13x8 prop on them. Some guys are gitting over 10,000 rpm on 20% fuel. I personaly would not run my engine that high. I am getting around 9600 on the APC 14x6 prop and the engine is really starting to come to life. I have about 1 1/2 gallons of fuel through it and just adjusted the valves for the first time. I flew it for 2 hours doing touch and go landings the other day. I make about 60 landings until I used all of the fuel that I had with me. I was the only one at the field. Man that was a lot of fun. This engine is awsome I am going to get me another one for a VF Edge 540.

Rick