Pitman part number?

Thanks for the catalog download. Will be useful as I learn and move along with the car. However the steering box I have bought, the year of it is unknown to me. It isn't an 1970 box
Look on the gear for any part numbers.
Many times the casting never is not exactly the same as the part number.

You might find a date number too.

If it was me I would first start with what was called out for on your car. The spline size and count is the deciding factor. The shape and whether the ball stud points up or down will need to match the ideler arm on your car now.