I'm kind of in the same boat as the OP. I have a 49 half ton and original wheels which are 4.5". Been trying to find tires to fit but most tire specs don't go that narrow..or even close. I would not mind going to a later OEM style wheel if not too spendy... May be time to visit a junk yard, but need at least three wheels (incl spare) that will fit my disc brakes to be added later.
I have bias plys on now and really hate them...wander all over the road and yes, I'll have the steering checked out too.