Very interesting articile on Feylí Kurds
Pahli (Feylí)
The Pahli (Kurdish: Pehlí, پههلی also called Fayli or Faili) Kurds are an integral part of the Kurdish Nation, speaking the Laki dialect of Kurdish.
The roots of the Pahli (Fayli or Faili) Kurds go back to the Indo-European immigrants of the 1st millennium BC. The Pahlis are roughly equally divided between the followers of Shiite Islam and the native Kurdish religion of Yazdanism (the Ahl-i Haqq branch). Conversion into Shi'ite Islam among the Pahli Kurds began during the reign of the Safavid dynasty in Persia (1507-1721).
There are many folk stories and etymologies for the "meaning" of the name Pahli/Fayli/Faili. In his book, Mu'jam al-buldan, the geographer Yaqut of Hama notes in 13th century that the Pahli/Faili who reside the mountains separating Persia from Iraq are called Faili/Pahli because they are as huge as elephants (from "fil", Arabic for elephant)! Others proposed that the name was that of a ruler of the area, given later to his subjects. Some of these folkloric accounts are discussed by Khusrow Goran in his book Kurdistan Through Eyes "volume I (Stockholm, 1992).
The historical fact on the root of the name of the Pahli is fully clear. As M. R. Izady notes in his work (The Kurds: A Concise Handbook, London, 1992), the territory inhabited by the Pahli/Fayli Kurds was known as "Pahla" (meaning "Parthia") since the 3rd century AD. The area boasted to one of the most important Parthian settlements outside Parthia proper (or Khurasan). The name "Pahla" was likewise used for the area by the early Muslim geographer until the 13th century, after which the name "Luristan" gradually came to replace it. The Arabic texts recorded the name as "Fahla" or "Bahla", (Arabic lacks the letter "p"). From "Fahla" has since evolved Faila and Faili -- the modern name of the Pahli Kurds. In fact, there is still a small town called Pahla in the south of the major city of Ilam in South Kurdistan which is the heart of traditional settlement occupied by Pahlis.
http://www.kurdishacademy.org/?q=node/46