I made this conversion on my 70 cuda years ago. You will need a shorter column as the power box is much larger. You should be able to find a PS column. In my case, I found a box off of a 71 cuda, the pump came off of a 73 charger (same as 70 cuda pump). Becareful with the pittman arm. There are two different sizes and I am doing this from memory - The 70/71 pittman arm will not fit the 72 & newer box. Make sure you get the brackets with your pump. The complete project took me about 3 hours for the conversion. The only speciality tool is the ball oint cracker wich you can get anywhere.
Good luck