 Lucas had wanted his wife, Marcia, to edit American Graffiti, but Universal executive Ned Tanen insisted on hiring Verna Fields, who had just finished editing Steven Spielberg's The Sugarland Express (1974). Fields worked on the first rough cut of the film before she left to resume work on What's Up, Doc? (1972). After Fields's departure, Lucas struggled with editing the film's story structure. He had originally written the script so that the four (Curt, Steve, John and Toad) storylines were always presented in the same sequence (an "ABCD" plot structure). But the first cut of American Graffiti was three-and-a-half hours long, and in order to whittle the film down to a more manageable two hours, so many scenes had to be cut, shortened, or combined that the film's structure became increasingly loose, and no longer adhered to Lucas's original "ABCD" presentation. Lucas completed his final cut of American Graffiti, which ran 112 minutes, in December 1972. Walter Murch assisted Lucas in post-production for audio mixing and sound design purposes. Murch suggested making Wolfman Jack's radio show the "backbone" of the film. "The Wolfman was an ethereal presence in the lives of young people," said producer Gary Kurtz, "and it was that quality we wanted and obtained in the picture."
