Long Term Storage

What are the risks with an engine (O-320) that has been overhauled and then not used for many years without special corrision prevention treatment? What parts may require replacement? I am considering buying and will inspect to insure no "significant" corrision, but I can not see everywhere.

The egnine was not run after rebuild so the rings have not seated. What would I look for to insure there is a low likely hood of problem with the rings seating?

How much do you think an overhaul of an engine like this would cost to bring back to acceptable shape. The engine has had no damage just hours on it before last overhaul in 1982.

Storage

Larry, Some would depend on where it was stored. In AZ or in FL makes a big difference. If it is from a humid environment and not protected it WILL have corrosion in the cylinders! This corrosion will probably be to an extent that the engine cannot be turned over by hand or with a starter. Even in AZ it likely would have some rust on the cylinders. Inside the case MAY be ok in a dry climate. Here is the EAA link to storage. http://members.eaa.org/home/homebuilders/operating/articles/Engine Storage.html
IMO the engine is probably going to need interior work! Getting it boroscoped would be a start but that won't tell you much about in the case and what has happened there. I would not pay much more than core value from what you have described as you will likely need to split the case and overhaul it again. Remember "The agony of poor quality lingers long after the sweetness of cheap price has worn off!" There are lots of engines out there and it is always nice when they keep running with a minimal number of problems. Best of luck. George