Stepper Specs?????

I have two old steppers. The manufacture date is 05/90 and they are
Pacific Scientific 21-3437D200-F075. Does any one know where to find
or have specs on these motors. I am building controllers for them
and need to know voltage and amps. Also I would like to know torque.

I have figured that they are 200 step motors base on observations and
the D200 in the part number.

Thanks