Proportioning valve / rear brake problems

I just installed the wilwood front disc brake kit on my 69 dart, the backs are still drums. I have the proportioning valve and the residual pressure valve installed, does it matter what order they are in? With the proportioning valve set so that the fronts get the most juice, the back left will still lock up first. The back right does not lock up and niether do the front, only the back left. Any ideas? I also have a new m.c. from wilwood, which we did bench bleed first.