Manual brakes proportioning valve?
 

I have an 84 GT we converted to manual brakes. We can't seem to get any pedal out of it. I upgraded the front brakes to ones from an 88 GT. Do I need an 88 vavle or are they the same? We bench bled two master cylinders and put two quarts of fluid through it. We get fluid out all four wheels, but when you hit the pedal it goes right to the floor then after about 6 or 7 pumps the pedal acts like it should. Anybody have any advice on manual brakes or know what I am doing wrong?