§ 53-a. Department heads. The town board shall appoint the head of any department of the government of the town established or created in accordance with the provisions of this article. Such department heads shall be principal executive officers of their respective departments and their offices shall be in the unclassified service, and unless their titles are otherwise designated by the town board, they shall be known as directors. Salaries of department heads shall be determined in the same manner as is provided in the annual budget for the salaries of other town officers, provided, however, that where the duties of a department head are increased, altered or diminished by local law and to the extent funds are available therefor, appropriate adjustment may be made in such local law in the salary of such department head.