RE: TT .91F Pre-Ignition "Girgling sound while flying"
If the RPM is dropping from 11-12,000 to 4-5,000 at full throttle something is seriously wrong. Typically when you have detonation RPM will drop just a little. If detonation was causing it to drop that low the engine would have serious damage at this point.
I would try richening a few clicks at a time to see if the problem goes away. This might point to a fuel system problem. I think you will find your problem here.
Stop worrying about the cams. You don't get a cam diagram for a good reason, it's not needed. If it makes full power at times chances are the cams are fine. Have you checked the valve lash (clearance)?
After it happens in flight and you land, does the problem occur on the ground immediately after landing?
Does the cooling arrangement work?