When installation of the lot and block system has been completed, the division of said system having custody of the plats and plat books and the upkeep of the same shall be transferred to the deed registry office of said county, and the files, cards, indexes and records relating to the liening of county taxes shall remain in and be maintained by the office of the controller of said county. The deed registrar and the controller of the county are hereby charged with and required to operate and maintain the several portions of the lot and block system placed in their custody, as herein provided.
16 P.S. § 3704