Disc brakes still not stopping good

Four wheel SSBC disc brakes on the car now with 4 piston fronts and single piston rears. Had a 1" bore wilwood master cylinder that just would not bleed after many attempts. So I put the disc/drum 1-1/32" master on that I was using when I had drums on the rear and disc fronts, and removed the residual valve. Have a in line proportioning valve on the rear brake line under the car near the center of the door. Got a good hard pedal but the car just does not stop good. Just kind of lazily comes to a stop with hard push on the pedal. Any ideas on what could be the problem now? Help???