It's Gentle On My Mind, performed by Lucinda Williams.
Originally sung by Glen Campbell, Gentle on My Mind, written by John Hartford won four 1968 Grammy Awards.
Hartford's inspiration for this song was the movie Doctor Zhivago. After watching the film, he sat down and wrote the lyrics in about 15 minutes.
Country music group The Band Perry covered the song in 2014 for the soundtrack of the documentary Glen Campbell: I'll Be Me. - SongFacts.com
Check some of the best scenes from Will Ferrell's Talladega Nights: The Ballad Of Ricky Bobby, compiled by Filmschoolrejects.com
And see list of songs and scene descriptions for this film at TuneFind.com.