Dual citizenship to Italy?

I have read several places that a person can get dual citizenship to Italy with no generation limit. After researching i am still unsure if I'm eligible. My great great grandfather was born in Italy in 1870, he came to America in the late 1800s I'm not sure what year but he is listed on the 1910 US census, along with his wife and children, so I'm guessing it was the late 1800s when he migrated. Both of his parents, my great great great grandparents, were born in Italy also and from my knowledge they did not migrate and remained in Italy. Also, my great great grandmothers parents were born in Italy. I do not know what year my great great grandfather was naturalized or how to find that info out. So with this given information, am I eligible to apply for dual citizenship? And how or where do I go to start the process?