I want to run their 15 x 8 inch wide in the rear. This would come with a 4.25 in back space. From what I can see this won't clear? Most posts say to go with the 4.5 or more. I have a 12 bolt with wilwoods on a 69 that sits about 3 inchs lower. I dont want to rub. So can I run these? Do I need to go to a 7 inch wide wheel to be safe? How about the front? What backspace is needed for those to be safe. Thanks much for any help

4 3/4 inches of backspace is good for the 8 inch wheels all around. you could do as little as 4 in the rear, but you'll probably have to roll the fender lip, especially on a '69.