Rather just an edit, I was rethinking my comments above.
If you have good mechanical skills, a rebuild seal kit is available from Rock Auto or many other vendors, is not expensive. It is not that hard to take a PS box apart, but you need to do your research on the process. There are many videos on YouTube, some are crap, other ok, but that is how I learned to do mine. It's not getting it apart and cleaned up, it's getting it back together with correct preloads. There has been a lot posted on rebuilding. The main areas of concern and why you may have to buy a new or rebuilt, is wear at the seal area on the sector shaft, (which will need to be machined and hard chromed) and wear inside the rotation valve body due to the 3 teflon seal rings wearing into the casting. If these wear groves are more than a few thou deep, (.003-.005") it may not work at it's best. In the v/r box, there are 24 balls, 12 are very slightly smaller and these MUST be reinstalled alternatively. If you have excessive free play on your steering wheel, more than 1" either way, these balls will need to be replaced with larger ones. Ford used to sell ball kits in 5 different sizes, but now nla. These balls measure to 5 decimals but I found from a rebuilder that various sizes can be bought from specialist manufacturers. At this point, if your box is too worn out, you will need to buy a replacement or have yours professionally rebuilt. Saginaw PS boxes are a GM product, used extensively on many GM products, so there's a good chance that you can find a rebuilder near by. Parts from several GM cars can be interchanged and it is possible to build your own fast ratio box.
Not wanting to overwhelm you on this, but steering is not something to play with. Other parts to check in your steering system are the drag link, tie rod ends, pitman arm and idler arm. some or all of these may need to be replaced as well. When you do an alignment for radial tires (tyres) I had mine set at 1/16" /side toe in, 3 degrees castor, camber; left 0.5 * right 0.8* which is pretty good I found.
All of the above is from what I have learned over the last few years and not expert advice. It's up to you to decide what is best for your budget and experience. There are several members with lots of knowledge, Bentworker being one of them. Ask questions.
First pic is the rotation valve assembly, second is sector shaft that has been hard chromed and ground (about 1" up from splines)