Apparently this is a question a lot of people have asked. And no one knows the answer for sure. Here's a link to one of many discussions:

http://wanderingtrader.com/travel-blog/fun-things-to-do-in-sicily-godfather-shooting-locations/

Ntra la porta tua lu sangu � sparsu,
E nun me mporta si ce muoru accisu...
E s'iddu muoru e vaju mparadisu
Si nun ce truovo a ttia, mancu ce trasu.