Update, after checking the 440source site. I think the thinner one is a 71 and earlier "6pack dampener" because of the off set pulley bolt pattern. I can't use it as it's not cast.
The thicker one that says cast crank has an symmetrical bolt pattern. Now I guess I need another symmetrical pulley because the one i have is not symmetrical. or can I just open up one of the holes slightly on the pulley to make it symmetrical?