Ford reported the sale of its vacant Milpitas plant.

The assembly plant, which closed in 1983, was sold to Mariana Financial, a Los Altos, Calif.-based real estate firm, which plans to make it an office and research park, Ford said. The price wasn’t disclosed. The plant, outside San Jose, was one of two called on in the mid-1960s to handle an unexpected overflow of orders for the newly introduced Ford Mustang.