OK I don't know how but I was measuring wrong. All the lines currently on the truck in stock form are 1/4", except the lines on the rear axle. They are 3/16". So should I stick with 1/4" lines for everything, and 3/16" for the lines on the rear axle? Im waiting for my pedal assembly to be delivered so Im looking at ordering all the supplies that I need now, so that I have them for the weekend when I go to install it. Im going to plumb in the combination valve so that its there when I switch the front drums out for disc brakes.