Hours on an O-200 is fairly meaningless, compared to being sure of it's condition. I've flown high time O-200's (3600hrs since overhaul) which were fine, and when disassembled were still fine, and I've flown engines fresh out of overhaul, which were really pretty poor. Sometimes it's the devil you know verses the devil you don't. It's only after the first well done inspection in service you know what you've got.
That said, more than other engine types, O-200's have some tolerance for non-ideal condition, before you really begin to notice a loss of performance in the plane.
In good conditions, you can get a 150 (with 10 flap!) off the ground with 2200 RPM (about 75% power). Yes, it takes a lot more runway, and the climb is poor....