It is a 1964 1/2 289 D code engine with an Eaton pump.
When I take the fan belt off the power steering pump and drive it without power steering, it doesn't pull at all. Why would the power steering pull to the right?
check the control valve adjustment nut as it may have come loose or just needs adjusted.
On the drivers side of the control valve take off the end cap and readjust the nut.
Tighten to 90 inch pounds, dont over tighten or it will break!
then back off 1/4 turn. this is the factory setting.
if it still pulls then turn the nut in or out a 1/8 turn to stop the pull.
or the control valve my have a internal leak, rebuild it.