OKUMA 1 3/4" I.D. Turret Lathe Tool Holder Tooling Block 80mm X 45mm BHP 1.750
I believe this to be most similar to the OKUMA A118-8445 or the HAAS HSL30-8445 tooling block. Bolt hole pattern: 80mm x 45mm. This tool block is missing 3 of the side set screws.