Power Disc Brakes not working on hard stop?

Hey all I wanted to close this thread with where I ended up.
Last fall I replaced the rear brake line between body and rear axel. it had been plugged. Once I did that and adjusted the the manual proportioning valve I got better braking overall but still had a hard brake pedal - didn't feel like I was getting as much brake pressure as I should on the front disc. I replaced the master cylinder when I got home this spring - so I have a matched booster and Master cylinder and can eliminate that as an issue. Currently I still have a hard brake pedal and it stops within 2 inches of travel when applying. Overall the car stops well even at speed. I'm still not totally happy with front braking pressure on front disc's but think I'm at the limit of the systems capability.