Could be a deal...
This engine came in:
Varga, Kachina 2150A
Robinson R-22
Cicare Cicare AG (French?)
It's a 150HP, 7.00:1 Compression at 2,700RPM, fixed pitch (only) and it can be converted to a 160HP (I think) with out changing the cylinders. (If it came out of a R22 it could be tired, chopper engines work hard.)
The biggest negative or at least the thing I would consider the biggest draw back is it is a conical mount (I think). Research comical mounts Vs. Dyna focal. Dyna is far superior in every way. The down side of conical is more vibration and more engine sag, especially with plan old engine mount bushings. LORD engine mounts makes a Dynafocal style "puck" isolators that fits in the conical mount. They help a lot, but cost $65-$75 each (Like dynafocal). I consider LORD to be the best you can get in engine mounts of any kind BTW. However with that said if I was on a budget and the price was right (free) I would consider it.
ECI can convert the case to Dyna focal during rebuild and the cost is not terrible, but it adds up on top of a rebuild. Contact ECI, the price info is on their web site (I recall about $800?) but the engine must be torn down, with associated cost.
I am in no way trying to talk you out of it, but I am telling you all the down sides. As you said good deals are not always good deals. On the other hand at almost $20,000.00 for a new engine, price does matter. Bottom line a conical mounted 150HP with a Sensenich prop in a clean light RV really flys. Many people must have the latest, greatest, best and biggest, but this could be a deal. Now if they want several thousand dollars and it needs a rebuild, it could end up costing well over $10,000, plus purchase price, to bring it up to speed and that is if every thing is OK on the innards. By the time you add purchase, rebuild, modification (mount/160HP if you want) you may only be a few LARGE Bills less than new?
If it is a working engine to use as is you could just buy it and use it for a while and when you have more cash install a better engine (180hp?). A real cheap way to fly, assuming the price is right and the engine is really in good health and airworthy as it. The down side to that is a new engine mount (dynafocal) cost the better part of $1000, if you change engines later.
Good luck George