Mike as i recall they are close to 1/2"; I just replace a power steering pump and the gal has them.
Two have a counter bore on one end to slide over the indexing dowel with a reduced shank on the opposing end and two are flat. You will also need longer bolts.
If you are referring to the M-2005-GT kit, I seem to remember that the spacers weren't that thick, maybe 1/4", more like thick washers. Per the Ford instructions (attached) for this kit, the power steering pump bolts are reused. You might try the techline, 800-Ford788, if you need exact specs.