The 871 unit, 792,499 square-foot property was built in 1974. It sits on 23-acres at 14000 Biscayne Boulevard. Blackstone financed the deal with a nearly $90 million mortgage from Wells Fargo. Units range from 510-square-foot studios to 1,100-square-foot two-bedrooms and include balconies, according to Portofino’s website. Details…