OKUMA 1 1/2" I.D. Turret Lathe Tool Holder Tooling Block 80mm X 45mm BHP 1.50"
I believe this to be most similar to the OKUMA A118-8435 or the HAAS HSL30-8435 tooling block. Bolt hole pattern: 80mm x 45mm. This tool block is missing 1 of the side set screws.