It is narrated from the Prophet (SAWA): Who resides Sura Al-Kahf on Friday, will be granted forgiveness till next Friday and three more days and will granted Noor (light) which reaches the sky. (Majma' al-Bayan by al-Tabrasi, Volume 3, Page 447).
It is also narrated from Imam Zainul Aabideen Al-Sajjad (AS): Who recites Sura Al-Kahf every eve of Friday ( Laylatul Jum'ah) will never die but as a martyr and will be in the day of Judgment with the martyrs. ( A'lam al-Deen by al-Daylami, page 371).
Similar meaning was narrated from Imam Jafar Al-Sadiq (AS) in Majma' Al-Bayan 3:447.
Wassalam.