If it was my truck, and I wasn't overly concerned with originality, I'd go with a radial snow. P235/75r15 became the default 1/2 pick up size some time ago (after L78-15 etc) and will be readily available at any tire store. I checked to see if Cooper still makes the Courser Traction, and they do in 700-15 and 750-16, but they're limitied production now and very expensiive.