Power steering upgrade ?

I am posting here for my Dad (he has no computer and lives in another state) who would like to upgrade his 1973 F100 econoline from manual steering to power assist. He would like to know what late model Pump, lines, box, etc. will fit or could be made to fit his van. His van has 302 V8 with a standard 3-speed transmission.
He did just finish upgrading his 1965 F100 to power steering and power disc brakes. Now he wants to do the same with his work van. I have been mostly a GM owner and have been of no help with his Ford products.
Thanks for any help!