Planning Research Corp., a leading provider of engineering and information services, announced the appointment of a new president and chief operating officer yesterday as part of the company's recent reorganization.

Wayne Shelton, currently a senior vice president with the corporation and president of PRC Government Information Systems (GIS), has been named president and chief operating officer of PRC, a new position that the McLean firm created as part of the reorganization.

John M. Toups, who had been president of PRC before the recent series of management changes, will continue as chairman and chief executive officer. Toups had been president and chief executive officer since 1978 and was named chairman in 1982.

Stuart C. Johnson, formerly president and general manager of Systems Development Corp.'s Standard Products Group, will succeed Shelton as president of GIS. Johnson also has been named a vice president at PRC.

Toups said the appointment of Shelton as president and chief operating officer is a direct result of PRC's continued growth and the need for additional operational management required to accommodate that growth.

PRC reported total revenue of more than $320 million and net income of $11.4 million in 1984.

The company beefed up its computer systems know-how earlier this year when it acquired Kentron International Inc., a Dallas systems engineering firm. PRC also bought Medic Computer Systems of Raleigh in a transaction that was completed earlier this year.

In another expansion move, PRC recently announced that its Business Information Systems is extending LoanExpress, a mortgage information and loan processing service, into the Tacoma, Wash., and Phoenix metropolitan areas.