I don't believe that Dallas Winston (or any of his friends in The Outsiders) ever reveal any particular dream that he hopes to come true. Dally is proud of his long police record; he misses the gang fights and the streets of New York City; and he spends some of his non-gang related activities as a rodeo partner of Buck Merrill. Dally hopes that Johnny Cade will "get tough" like he is, and there is no doubt that he wants to see Johnny survive his burns. In the end, it may be that his dream is to die when he commits "suicide by cop." But I have been unable to locate any specific references in the novel to a particular dream of his.