Allen C. Miech, 51, president of Transamerica...

Allen C. Miech, 51, president of Transamerica Financial Services, Transamerica Corp.’s Los Angeles-based consumer lending subsidiary, has added the title of chief executive. Arthur E. Van Leuven, who had been chairman and chief executive of Transamerica Financial Services, has relinquished both titles in anticipation of his scheduled retirement Nov. 30, 1990, at age 65. Van Leuven will retain his posts as chairman of Transamerica Finance Group, and as an executive vice president and a director of Transamerica Corp., until he retires.