Why crossover steering

[KyFarm]

I would like to know the advantages and disadvantages of crossover steering.

I don't know if its just the 33" tires or what but this truck of mine wanders around the road pretty good. The steering is tight, by that I mean it seems that input from the wheel translates well to the front end without much play in the wheel, but if you hold the wheel straight the truck tends to go right or left on these old country roads that I drive.

The truck is a '69 but the front axel is from a '72 so it has power disc brakes.

So what can be done to tighten up the front end? All help is greatly apprreciated