16X8 is a good prop as stated above. Try the Perry carb for it, makes a nice power increase for $35. Top rpm should not be more than 9000 static. These are not high reving engines like todays crop are. Feed it 10 to 12% oil after break in (all castor) or 16 to 18% oil (castor/synthetic blend) fuel and yes I have the ST supplement that explains this (for all those that think this is bs). Nitro % is up to you, I run 15% nitro Omega in my 2000 & 2500 with great results. They also like OS F plugs. With a little care they will last a very long time.