Does the shortened pitman arm change anything in the steering. Like how much the wheel turns?
Depends on the car and the steering type. Prior threads seem to indicate that the two-tooth box has more travel than the seven-tooth box, and so it is common for the seven-tooth steering box to go lock-to-lock before the wheels do, meaning that the turning radius increases.
Since the two-tooth steering box has more travel, there is usually enough to make the wheels go lock-to-lock with a shortened pitman arm EXCEPT that the shortened arm has the effect of moving the end of the drag link at the extremes of travel. Because of the differing geometry at the extremes this means that the centers of travel of the box and the front end no longer coincide, and the spindles will not go to the stop in one direction. (Can't remember offhand which direction; I'd have to go out and look at the car.)
This is usually not a significant problem. If it bothers you, Snyder sells an adjustable drag link which can be fine-tuned to make the travels coincide again. From what I've read here, most people don't bother.
So, bottom line: A short arm on a two-tooth box often increases turn radius a little in one direction, and this can be compensated with an adjustable drag link.
A short arm on a seven-tooth box will probably increase turn radius in both directions, and one direction more than the other. An adjustable drag link will even it out, but will not restore the original turn radius.
In either case, the increase of turn radius is not considered significant by most owners.
Joe