Does anybody know the output shaft diameter and number of splines? I'd rather not try to take off the pitman arm and screw something up if I can't find something to replace it with.
I don't know the answer, but the 525 box is what was used in S-10 trucks (and other stuff, but the S-10 is the common donor to find the 525 manual box). So that might help you with looking up specifics.
The Saginaw 525 steering box was widely used in many applications: 1965-1991 Chevelle, Camero, Impala, Nova, C / K trucks. 1972-1986 Jeep CJ. So many donors out there. They are also easily reversed. You will encounter several spline counts depending on application.