I can understand why you might want to just replace the motors but there is no real need to as Mike has said depending on what drivers are fitted & their dipswitch settings you can normally get all the info you need, a lot of the details about the motors can also be found elsewhere as well, number of wires & their colours is a good clue, the centre to centre measurement Mike told you to take will indicate which series they are, look to be nema 34 but pictures can be deceiving
Once you know what series they are the body length can help in narrowing down what sort of power rating they have.
Where did you buy it? Can they not help at all ??