The Director of the Department of Industrial Relations shall determine the general prevailing rate of per diem wages in accordance with the standards set forth in Section 1773, and the director’s determination in the matter shall be final except as provided in Section 1773.4. Nothing in this article, however, shall prohibit the payment of more than the general prevailing rate of wages to any workman employed on public work. Nothing in this act shall permit any overtime work in violation of Article 3 of this chapter.