I have bench run the engine for a couple of view minute sessions.
I am getting 7200 revs on APC 16X6 prop and 20/20/fuel.
Although set very rich it was getting so hot that throttle barrel got stuck.
Cooled down the engine and tried again on even reacher setting, but with same result.
This another mystery.
At least some succes, when cold, the compression is back and it is quite OK.