If “you gotta be a moron” to be a good fighter, what do you have to be to make a good Broadway musical? A Tony award-winning songwriting team is trying to find out. Lynn Ahrens and Stephen Flaherty and bookwriter Thomas Meehan are creating a Broadway musical based on the 1976 movie Rocky. The film’s creators and producers, including Rocky star and screenwriter Sylvester Stallone, had a private reading of the script in April, Meehan said. Meehan described the show as having a small orchestra and cast, with about five principal characters and a plot similar to the first installment of Rocky. “At first I thought, all the world needs is a Rocky musical,” Meehan said. But he said he looked at the film, describing it as a “David and Goliath story” with “beautiful construction.”