Where to get new front disc for my -67 Barracuda

Mattax, thanks for your comments, mine disc and hub is Kelsey Hayes, that is sure now. I describe the problem wrongly. Actually there is knocking with low speed, when I drive faster naturally I can't hear it. The reason is that disc is not in balance any more, there is run out on disc and brake shue is knocking against disc surface. I haven't check the run out yet. Maybe it will disappear once I check and adjust the wheel bearing. Anyway I will replace new pads and check the pistons as well.