MONTEBELLO, Calif. -- A 10-mile stretch of Southern California freeway, closed when a gasoline tanker fire melted part of an overpass and snarled rush-hour commuter traffic in and out of Los Angeles, is scheduled to reopen Friday after the overpass is at least partly demolished. Engineers examined the blackened, pitted Paramount Boulevard span over State Highway 60 in the suburb of Montebello on Thursday and determined that at least the eastern lanes would have to be torn down. Heavy tractors moved in to begin the work immediately.