In S.E. Hinton's novel, The Outsiders, Johnny Cade was the youngest member of the Greasers. His best friend was Ponyboy Curtis, because he and Ponyboy were both the youngest members of the group. However, Johnny idolized Dallas Winston. Dally, as he was called, loved Johnny. It is the only person he did love. Johnny loved and idolized Dally because Dally "had his back." Johnny was unloved and abused by his parents. The only people in his life that though of him were the Greasers. Whenever Johnny got beat up by the Socs it was Dally that stood up for him and it is Dally who looked out for him in the fights between the Socs and Greasers. To Johnny, Dally was like the "Southern Gentlemen in Gone With The Wind." Johnny felt Dally was gallant. It was Dally that Johnny and Ponyboy went to when they got into trouble. Johnny accidentally killed Bob of the Socs because he was trying to stop them from drowing Ponyboy in the fountain. Dally helped them out of the jam and then saved them again at the church.
You asked why Ponyboy does not feel the same toward Dally as Johnny did. Ponyboy had two older brothers, Johnny had no one but Dally. Ponyboy was really close to Sodapop and he had his brother Darry to look after him. He and Darry fought a lot, but Darry was responsible for raising Ponyboy. Johnny could not look up to his parents so he attached his respect and love to the one person who was always giving him time, attention and love. Ponyboy didn't need this. He got it from his brothers.
".. there are two things that have meaning for him; jockeying on ponies (the "only thing Dally did honestly") and Johnny."