i have a 1974 359 peterbilt with a 903 and it does not have power steering and i would like to put it on if i can. does anyone know where i can come up with the parts?

 

you should be able to find a Ross ps box and order the right drag link and a pump could be belt driven.
I did the same thing to a 1970 IH 10 wheeler I had and got all the parts from a wrecking yard. also the wrecking yards that dismantal big rigs have some smart guys you can pick there brains for info .ask me how I know
R