I want to add power steering to a '68 Chevelle that came from the factory with out it. Is the only thing I need to do is get the pump and swap out the steering box? Or is there more to this, like changing the whole colume? Are there kits for this?

Thanks in advance for the advice.

Oh BTW, the factory 307 is coming out and 350 going in. Figured I add that in case that would change anything as far as the PS goes.

You need the power steering box, pitman arm (think they are different), and a pump,the brackets and pulleys for the pump and crank.

Might as well look into an AGR quick ratio box. They are popular on TC.
What type of pulley setup are you running?