At Stake, a Super Bowl Berth, and a Loaf of Sourdough Bread As inspiring pregame speeches go, the New York Giants head coach, Tom Coughlin, could perhaps do better than, "Our mayor needs that sourdough bread!" But as the Giants prepare to face the San Francisco 49ers on Sunday for the N.F.C. Championship, Mayor Michael R. Bloomberg will indeed have more on the line than the typical fan. If the 49ers win, Mr. Bloomberg has agreed to rename 49th Street in Midtown "49ers Street" for one day, hanging a special sign made by the Department of Transportation. Mr. Bloomberg must also send the San Francisco mayor, Edwin M. Lee, a dozen bagels from Bagel Oasis in Queens. A Giants victory, meanwhile, would require Mr. Lee to drape a San Francisco cable car with flags for the visiting team and send "classic sourdough bread" to New York, Mr. Bloomberg's office said. Engaging in the kind of toothless trash talk that has become typical of political sports wagers, the mayors still expressed uncommon gridiron bravado for two men whose combined heights total about 11 feet. "Just like Hakeem Nicks ran right past the Packers" secondary, the Giants are going to breeze by the 49ers on their way to the Super Bowl," Mr. Bloomberg said. After Sunday, Niners fans will be left with a taste as sour as their famous bread, and the Giants will have their sights set on another trophy. Mr. Lee countered with a prediction that "the Giants will have to leave their hearts and their Super Bowl hopes in San Francisco." For their teams" victories last week, each mayor made off with some treasures from the losing city. After the 49ers topped the New Orleans Saints, 36-32, Mr. Lee won fresh Louisiana seafood from Mayor Mitchell J. Landrieu of New Orleans. And the Giants" 37-20 victory over the Packers earned Mr. Bloomberg cheese curds and root beer from the Green Bay mayor, James J. Schmitt.