67 and 68 wheel wells are not as condusive to over sized tires as 69 and later --different design.
I've got them (15 x 7) on my 68 (from previous owner --a new set of tires and yes, I'm too cheap to not run them!). They will work, but they will also bump and rub --even with a firm ride (mine does).
Where do they rub? Obviously, in a full turn of the wheel, but also over bumps running straight. And this is different from bottoming out. The actual rub on mine is more on the outside of the wheel and wheel well. It's actually more of a scrape. So far --after about 3000 miles-- no noticeable damage to tire or wheel well.
Yes, they do look great --if that's your preference. But they don't look original.
Take a look at this thread and the other thread(s) it refers to:http://www.camaros.org/forum/index.php?topic=1346.msg7824#msg7824