[1958Warrior]

That is a pretty rare find there, I've seen 2 and they were no where as clean as yours looks. I think white and grey was the most common colors. What is the paint code on the truck. any history as to its origin?
If I was you I'd preserve it as is or put a period correct engine in it. If I remember right some GMC's had either Pontiac or Buick motors from the factory.