If there's nothing worn out in the front end,you might try adding toe-in,adjust maybe half a turn at a time,test drive,see if it helps. Remember how much you adjust,or write it down,so if it makes it worse or doesn't help,you can set it back to where it was.If that doesn't help,it might be worth it to find an alignment shop that knows I-beam front ends and have it checked.It could need a wedge shim under the axle at each spring to change the kingpin rake.
