Mike Post, who had made a name for himself producing the First Edition and their hit "Just Dropped In (To See What Condition My Condition Was In)
," produced the album. Speaking with the Archive of American Television, he explained, "Mason played me this one little song in A minor called 'Classical Gas.' And it really was good. He said, 'I just want to do bass, drums, guitar and piano.' I said, 'We need an orchestra for some of the vocal songs on the album, we can do a big, aggressive instrumental thing.'"
Post wrote a middle section for the song because it needed a bridge, and conducted the orchestra. The song became a huge hit and got Post into television - he became the musical director on The Andy Williams Show
in 1969 and went on to write many famous TV theme songs, including The Rockford Files
, Hill Street Blues
and The Greatest American Hero