clicking on the snopes link leads to more links
the SCR article states: "Clara was able to determine that the cars are located somewhere in the area of Sintra, near Lisbon."
Here are the links that the snopes link will lead you to:
http://www.intuh.net/barnfinds/index.htm
http://www.sportscarmarket.com/portugesebarnfind.pdf
then from the snopes links you can get to:
http://www.forocoches.com/foro/showthread.php?t=548055
http://www.sportscarmarket.com/articles/archives/1110