Hi there,I have a 66 mustang fastback with drums all around.We installed a dual master Cyl 3-4 years ago for safteys sake.. Now I have a disc brake kit for the front that I bought from ssbc about 3 years ago and now am getting ready soon to install the disc brake convertion. Being I have already installed the master Cyl where do I mount the Proportinal valve at and do the lines come out of that for the rear brakes only.Pic would be nice. I thank you for your time. God bless