Fluid volume doesn't necessarily relate to pressure. Most aftermarket (front) disc conversion kits use 3/16 front and 1/4 to the rear. You will find that the proportioning valves are designed for 3/16. I have installed numerous kits on a variety of vehicles and have not had a problem with this configuration.
Fred
Last edited by rfs56trk; 06/26/2010 11:27 PM.