How do those balljoints come out of the IFS pitman arm?

Grind the bottom of the arm (as it is mounted on the truck), then press out the joint.

you mean the top section? not the ball joint thing right?

The "cap" opposite of the tie rod end part this sticks out. I suggest cutting ot off with a band saw to start with, then grind till you can remove the tie rod stud... saves time/effort over just grinding...

Just grind off the edges of the cap and then the cap and stud will fall right out. Only takes a minute or two.

Or if you have a press, plop it in there and press the stud & cap out at the same time. :D