In The Outsiders, what does the blue Mustang symbolize?

The blue Mustang in S.E. Hinton’s story of boys from the lower end of the socioeconomic spectrum competing, often violently, with their more well-to-do counterparts from the more financially affluent part of town, The Outsiders, symbolizes the wealth and privilege of the latter. From the story’s beginning, Ford Mustangs serve a special role in the lives and dreams of Hinton’s characters. Mustangs were, to quote a passage from Chapter 1, “cool, sharp—like a tuff-looking Mustang.” The symbolism of this particular vehicle is repeated throughout the narrative, as when Hinton’s youthful narrator, Ponyboy Curtis, described the adversarial relationship between his group, the Greasers, and the boys from the wealthy families, the Socs. Discussing the attractive, well-kept girls who were part of the Socs’ world, Ponyboy notes that

... most looked at us like we were dirt—gave us the same kind of look that the Socs did when they came by in their Mustangs and Corvairs and yelled "Grease!" at us.

The Mustang is a status symbol in The Outsiders. The blue Mustang that assumes a role of prominence in Hinton’s story, however, carries with it an especially negative connotation. It belongs to the Socs and repeatedly appears in the negative context of attacks on Ponyboy, his brothers, and friends. Of particular importance is the role the car plays in one of the novel's most memorable if unseen developments, the brutal assault on Ponyboy's closest friend, Johnny. Describing the assault on Johnny by their enemies, who materialized in the blue Mustang, the car's significance is magnified as it becomes increasingly associated with it. Ponyboy relates Johnny's story as follows:

"There was a whole bunch of them," Johnny went on, swallowing, ignoring Soda's command. "A blue Mustang full ... I got so scared ..."

Again, in the following passages, the blue Mustang with four Socs in it again is emphasized and connected with the boys who beat Johnny. This time, for added emphasis, Ponyboy mentions that one of the Socs “had a lot of rings on his hand,” jewelry associated with wealth that was used to inflict nastier cuts on Johnny.

The blue Mustang is symbolic of the wealth and arrogance that define the Socs and helps to mark a strong contrast with the much poorer Greasers. It is identified with the character-shaping assault on Johnny, one of the younger Greasers who is a regular victim of physical assaults at the hands of his father, none of which involved the level of brutality meted out by the Socs. The blue Mustang is also contrasted with Randy’s “little old Mustang” that he dreams of using to depart this town and this life and begin life in a new setting—a setting in which he will be free of the second-class status that defined his and his friends’ lives.