Possible Clues:

• Gloria Gaynor's 'I Will Survive,' originally
• Back track?
• Something in back of a hit?
• Back of a hit record
• Unlikely hit on a 45
• The Righteous Brothers' 'Unchained Melody,' originally
• A sleeper hit may be on it
• 'I Am the Walrus,' for the Beatles' 'Hello, Goodbye'
• Hit bottom?
• Many an Everly Brothers hit