1965 273 power steering qustions

That was the same setup that was on my 65 Dart wagon, which is correct for 65 - earlier (and maybe 66 A bodies as well - I’m not up on stuff like that for 66’s). PS units used a 5/8th return line from the steering box to the pump and a fairly long high pressure hose from pump to to the box. Some full size Chryslers also utilized a U-Shaped PS fluid cooler with the 5/8th lines to match the hose size as you have