Looking at buying an approximately 40 year old 2 stage, 5 hp compressor. Appears to be a 60 gallon tank, but couldn't find any markings. Runs fairly quiet and fills to 120 where he has it set to shut off, but immediately drains out the "elbow valve" on the front of the compressor. The owner bought it for $2000 when he was in hs and has had it ever since. It is a horizontal tank and has no drain on the bottom. There are a couple of large plugs about 1/3 up the tank on each end, but he says he has never drained the tank, just a small filter mounted before the hose. They are asking $400. What do you think? I'll try to post a few pics in a little bit. Thanks