Former New York Stock Exchange chairman Dick Grasso is still advocating for Police Commissioner Ray Kelly to run for mayor. Since The Post reported this week that Kelly is being courted by former state GOP chairman William Powers to run for mayor next year, Grasso has been rallying his wealthy friends, including Ken Langone and Hank Greenberg, who we’re told are ready to start building a war chest for Kelly. Grasso told us, “I, along with many of my friends, have encouraged Commissioner Kelly to make a mayoral run. I think he would be a fabulous mayor, and many of my friends agree. Many Ray Kelly admirers, including myself, Ken and Hank, would get behind his fund-raising effort. I think Ray is the only person who could run as a Republican and win in a one-up race. I am not 100 percent behind Ray — I am 1,000 percent behind him.” Still, Grasso admits that Kelly has yet to signal he’s interested in running: “Many people have had the conversation with him, but Ray is a man of integrity, and it is totally inappropriate for him to talk about running for mayor while he is the police commissioner. But it would be great for the city if he would run.”