How wise/necessary to add power steering?

I've had/have both. Like you, a '69 Barracuda with a 340. I didn't really mind it with the small block. Now I have a '69 with a 383 that has power steering and clearly the reason the factory used it for the big blocks was front end weight. It's nice to have and DW likes it when she drives the car. I have manual in a '64 Hemi Dodge and its not bad at all but the steering wheel is much larger in diameter.

To add it to yours you'l not only need the box, pump, hoses and likely the correct crank pulley. You'l likely need to change out the steering shaft (because of length). Also, the input shaft at the steering box might be a different diameter (it was on my '64). which means a different coupler.

It is very possible and is done everyday, if it were me, I'd leave it manual. But it's your car and your choice. :-) Keep us posted!