Should be a Cleveland. Ford used them for the Mustangs starting in 1970. Could be either the 2V or 4V model. Know the 2V heads are stamped on the upper left with a 2. Not sure if the 4V heads have a 4 stamp or not.
Yes, 4V heads do have a "4" cast into the ends of the head, at the upper corners of the head.
Easiest way to tell a Cleveland from a Windsor is the water neck. If it's vertical, it's a C, if it points toward the radiator, it's a W. After that, the valce covers are different, c has a cast in timing cahin housing, windsor has a bolt on aluminum one.