Old engines
Elsewhere, it was mentioned, and not for the first time, that some pilots are not confident that "old" engines provide power as they would have when they were new. I resist this notion.
The engine does not know its age, it knows how it has been maintained. If it is maintained well, it will produce its rated power. It's simple physics. If an owner lets its condition deteriorate, it will produce less power at full open throttle, until eventually, it scares someone into knowing it needs maintenance.
If you believe that the engine you're flying will not meet the flight manual performance standards, then you have made the determination that the engine is not airworthy, and you should not fly the plane. It could not be more simple. For many fixed pitch prop airplanes, the Type certificate data sheet will specify a minimum and maximum RPM to be achieved static on the ground. This is an excellent way for a pilot to quickly assess engine condition and performance (assuming an accurate tach!). CS prop engines are not quite so straight forward in that regard.
I've owned my O-200 for nearly 31 years. In that time, I've put more than 3000 hours on it. It produces the same power now, as it did when I first bought it (well, probably a little more, I bought it as a near to TBO engine). I have maintained it over the years, and it has rewarded me with dependable power the entire time, with the only exception being a stuck exhaust valve once. Otherwise, perfect reliability and performance.
We cannot control the age of our engines, other than replacing with new, but we can control the condition. The performance will be based upon condition - so let's not blame age!