If you are speaking of the 51, I believe $400-600 was the range others have paid for having their similar models recored in the last couple of years. I think that's probably about the only correct option unless a used or better radiator comes along. Chances are that any used one will need work as well.
There was discussion on replacing 55-6 radiators with relatively inexpensive common Ford truck units.
https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=54085#forumpost54085 I'm not sure a definitive decision was made whether they will fit the earlier 51-4 cars.
Maybe not the best option and with the needed brackets and use of a different hose, wouldn't be stock looking if that's a concern. Your radiator guy might be able to find something close in size if you wanted to go that route.
This Post was from: https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=81398