Proportioning valve question
Be sure to shim the rear calipers, so that the opening where the pads pass through the caliper is centered evenly in the pad opening. I used a grade 8 washer to center mine, although any steel washer should be sufficient.
Also, check to insure that the rotor is not being held off it's mounting surface by the shoulders of your log nuts. In other words, make sure its seated fully on the axle flange. I had to chamfer the lug holes to allow my rotor to seat fully.
Another thing to check is that your rim seats fully on the rotor face. I had to use Wilwood's steel .250" hub protectors for my steelies to sit on the rotor flange correctly and make full contact with the rim face..