The name is more than likely Vallelonga for a few reasons. First, if the passport was issued in Italy, than I believe the person issuing it would have a better chance of using the correct surname, and of course, the passport is written as she gave the information. I believe the other name is definitely an Americanized version. I also checked www.stevemorse.org
website and found several persons leaving Caulonia for the US with the surname Vallelonga. You can also see here in one of the Indici of births I copied from Caulonia that the surname is spelled as Vallelonga..
I would request the birth record as Vallelonga :
Comune di Casignana
ZIP Code: 89041 Casignana (RC)
0964 860830 fax: 0964 860830
Hope this helps.