Here's a beautiful OS 91 FX engine. It has a new ring and new bearings and runs great. I have only run one tank of 10% fuel through it, so it needs additional break in.
I got this engine in a trade. It was on a 60-size airplane and had very low compression. I disassembled it, thoroughly cleaned and lubed it, and replaved the ring and bearings with brand new ones. That means I have about what I'm asking in the cost of parts.