Hi Pete,
I am looking for a value on a 1977 986IH. Tractor is fully restored with 8000 hours. It is in better than new condition. 
Wow…that is one sharp 986! Here’s look at (10) Highest Auction Prices ever on IHC 986 Tractors:
We filmed 8/15/17 central Indiana auction where 2nd highest auction price ever 986 sold…1976 model with only 1,123 actual hours on it, sold for $23,000. Here’s pic of it:
Another recent high selling 986 just last month…12/9/17 consignment auction in east-central New York, this 1976 model 986, complete restoration, canopy, sold for $16,250. Here’s a pic of it:
Nicest IHC 986 I see currently for sale by dealers around the country is this one…1980 model with 5,364 hours for sale in Burlington, NC, click here for info on it (pic below): https://www.machinerypete.com/details/100-174-hp/1980/international-harvester/986/19157893
Hope this info was helpful!