Rear Disc conversion super noisy?

I just finished a rear disc conversion on my 69 Valiant with an 8 3/4 rear end. I used a kit from Right Stuff and it all went together very easy. It makes a super loud noise when you apply the brakes normal, when I hit the brakes hard it is fine. It so freakin loud it is embarrasing. I have tried everything, turned the new rotors, scuffed and tappered the pads, made sure that the pads are installed correctly with no vibration. Right now I am wishing I would have left the drums on it stopped great. The only thing I can think of now is that I mounted the calipers in front as per the instructions, however most pics I can find of other systems show the calipers on the back. The noise is not brake squeek but a loud whirring followed by a loud rattle. I am getting pissed!