'89 Cav Brake issues

[goad]

Hi
I have replaced the front brakes including the rotors. Shoes on the rear as well as the Wheel Cylinders. Replaced the P/B Booster AND the Master cylinder.....
I have an EXTREMELY shoft brake where the brake pedal goes to the floor. I am trying to fix these before our 17 year old gets in a wreck.

We have bled the entire syetem starting with the master and worked our way around from the furthest port up......
I also have vacuum going into the booster (not measured)...........

WHAT ELSE can I possibly do????
Can anyone help?? Any ideas???

Thanks

Ken