If your Main spring is bent or twisted you'll need to contact Eaton Detroit Springs to get a new one made...all of our local Maryland/Virginia spring shops no longer custom make springs, they buy them already made and 1938 is off the radar for them.
https://www.eatondetroitspring.com/The frame horn is the front of the frame rail from the radiator forward...if your truck was in a wreck the frame could be pushed in or out causing the issue you have. Put a straight edge on the side of the frame and see if it's straight.
Mike B
