The Ford Motor Co. and union officials are disputing that an unwritten deal required setting aside 10 percent of hourly jobs for union-picked candidates, a practice alleged in a lawsuit by a former manager who claims he was fired for objecting to the hiring of unqualified workers. He contends that a nationwide agreement with the UAW violated federal labor law and resulted in hiring convicted felons and unqualified relatives of union officials. \"Ten percent seems like an ungodly number,\" said Hal Stack, director of the Labor Studies Center at Wayne State University. \"I\'d heard of that behavior claimed at a plant level, but not at a national level.\" Ford officials maintain that the plaintiff, a former labor relations supervisor, violated labor law when he improperly promoted union bargaining representatives to positions that should have been open to all hourly workers.