Great motors , but you do have to 'work' with them to get them under control.
If you haven't run at least 5L of fuel through them they are nowhere near run in, even then it's going to take a while, but hopefully the vibration when running will be reduced.
The exhaust: if it has the press in end it WILL blow off. Weld it in or replace with an OS muffler.
The carby is their biggest let down. WOT is set to max rpm not the fully open barrel as you would be used to.
Balance the prop, an expect it to take a while if you are using the APC 4 blades. They are the WORST balanced prop, off the shelf' I have ever come across.
Run the recommended fuel, as fuel makes a HUGE difference to their performance, especially vibration and wear. Keep an ear open for any detonation as it will destroy the pinion gear very quickly.
Prop it up, don't under prop it, as this also seems detrimental to it's longevity.
At present have just put a 61SP in a SeaFury and it is swinging a 4 blade 15.5" x 12" at 4200 rpm. I will be trimming the prop to get a bit closer to 5K (aiming at 4.8K) before it's maiden flight.
Keep us posted on how you go with them.