BOB COX General Motors officials said Friday they had notified about 1,100 dealers nationwide that their dealership agreements would not be renewed when they expire, part of the companys effort to restructure into a smaller, healthier enterprise.Many of the affected dealers are too small or are not economically viable and competitive businesses, Mark LaNeve, GM vice president of sales service and marketing, said during a conference call with reporters.GM did not release a list of affected dealers or numbers by states or areas.