I have a 1970 F100 Ranger 4x4 w/a 352 v8(1958 I think). It has a bad steering box and i would like to upgrade to power steering. Would anything from a 2-wheel fit or 4x4 only? What year trucks/cars can I get this box?

I did not think that the 1970 had factory power steering, I thought that the power steering did not start in the trucks until around 76. I do know that the mid 70's 2wd and the late 70's 4wd use a different steering box if that helps.

there are several models from 2 and 4wheel drives that will work but like EBSteve said they didn't come with power steering so you'll just have to search around and find soemthing that you can work with and build the mounts.
I've tried to sit here and imagine the frame rail on that truck but for the life of me i can't remember exactly what it looks like or i would suggest a box to start with.
Maybe i could with some pictures.

I thought they were PS?
I had a 71 250 that had it.
I think these are the ones mounted back behind the wheel

none that i have seen in this area had power steering boxes. but who knows.

My 72 F-100 came with manual and I spent a lot of time resserching and successfully put toyota pws on it. (bought everything from pirate too) the Ford 2wd box sits on the inside of the frame the 4x4 frame has a x/member right were the box would sit. made my own brkt and had to notch and reinforce the frame but works flawlessly. I didn't think it would hold up and though about the rats assist but works fine with 33X12.50.
Ford put the power expanding draglink on the 100s in 73 but that crap is too expensive and it don't work.

IS your box a three hole box located on the outside of the frame rail? (closer to the driver side). It still doesnt mean anything but a 79 and 79 2wd box might work. I am doing the same thing on my 74'

the 4wd power steering box is in front of the wheel and the 2wd is behind the wheel(closer to the column). I would think a late 70's 4wd PS box would work for what you got. got a picof what you are working with? I can tell you if it looks like my 79 Bronco box...