Its a 1965 Chevrolet Corvair. Do not know what paint it has, not factory original. Plus it has a clear coat (peeled away previously in bottom middle right as shown.)
My outside car gets covered, and the cover gets wet from both rain and my well (well is very deep and I get no rust stains). I used to fold up cover and place on the hood of my garaged car. I went on a trip and left the cover on the hood for 5 days and when I came back I had this water stain...