Looks like an Ingersoll Rand? Or possibly a Campbell Hausfeld?
The pro 4000 was manufactured by both.
Not sure about the 60 gal unit but, the 80 gal unit, new, runs in the upper 700.00 range retail. These compressors, regardless of tank size, have been popular for years and parts are plentiful. A bad head gasket will cause the unit to "loose" air while it is in operation due to gasket blow by.
Basicly making it inefficient. Once the tank is compressed, the gasket should have nothing to do with it.
By the way, the 5HP rating means nothing here. Both Ingersoll Rand, Campbell and others including craftman were successfully sued over this electric motors power rating. They wound up being measurably less than 5HP. You will still need at least a 30 amp breaker as well. But if you have priced similar units at 80 gal, the price is right on this one. Look it over!