original type tires for a '68

[low 84]

Hey guys can you help me out with something? A good buddy of mine has a '68 long wheel base stepside that he put a built '68 chevelle 396 in it. He is wanting to put the original size tire back on it. I work as a tech in a tire store so i can get him a good deal but i don't know what type of tires came on it.

he says that his dad ordered the truck new with tires that would normally go on a 3/4 ton even though it is a half ton. he calls the tires 6 ply 715's. I am not familiar with this sizing method i only know the metric size method.

what he wants is a tire that is the same height and similar width to the 3/4 ton type tires that came on it, it does matter if they are actually original type 6 plies, they can be radials.

can some of you guys point me in the right direction?

thanks very much,
ryan c.