Shared with you
Along with all the other songs that were rewritten for the movie perhaps one of the songs that was most worked over was "The Rumble Song" (Sometimes known simply as Quintet). Due to the outcome of the war council, the best man from each gang will fight it out fairly. The duel in the stage show is initially meant to be fought between Bernardo and Diesel. Diesel didn't appear in the movie, so the duel is between Ice and Bernardo. Also there is a part when Riff is talking Tony into arriving at the Rumble (I'm counting on you to be there tonight/When Diesel wins it fair and square tonight) which changed (We'll be a-backing you boy/You're gonna flatten him good) due to the change of the fighters.
The actors in the rival gangs were instructed to play pranks on each other off the set to keep tensions high.
The lyrics to "America" were substantially changed for the movie. There had been complaints that the Broadway version was too belittling to Puerto Ricans, in that the song mainly ridiculed Puerto Rico and Puerto Ricans. The movie lyrics emphasize the racism and discrimination that Puerto Ricans were subjected to in America.
Throughout the movie, Natalie Wood wears a bracelet on her left wrist, not for any aesthetic reason, but because she had injured her wrist in the scene of The Green Promise (1949) when she fell on the bridge that collapsed during the severe rainstorm, causing an unsightly bone protrusion on her wrist. She wore the bracelet to hide the injury. It became her trademark in all of her movies.
Riff and Tony repeat an oath of loyalty to each other: Riff says "womb to tomb" and Tony answers "birth to earth." On stage Tony's original answer was "sperm to worm," but this was changed for the movie because it was beyond the censorship standards of the time.
Russ Tamblyn (Riff) said that initially he was very unhappy with his dancing in the film, until Fred Astaire came over to him at the premiere and told him that he admired his dancing in it very much.