Guys, thanks for replying! In previous configuration the car had the same Wilwoods on rear and stock front discs. MC bore was 1.062, and everything worked good. When going to 9" I had Dr Diff put Mopar ends on axle tubes so I could reuse the Wilwoods.

You may be right on MC size. I thought I did the math correctly to determine size and the first MC I tried was a 7/8 bore. The one I have on there now is a 15/16 bore. The new one I haven't tried is either a 1.062 or a 1.125. It's one from Ehrenburg.

Rocky All bleeders are pointing up except one. The Lamb calipers cannot be removed like the Wilwoods, the rotor must be unbolted from the wheel to get the caliper off, not an easy job. However if that is the problem I will figure a way. I have tested MC by blocking each port as you suggest and in both cases it held vacuum steady.

My next step will be to try the larger MC, will report the results.