Single to dual master changeover

Hi all, I'm looking to change my '66 Valiant brakes system from the stock single stage master cylinder to a '67-up style dual stage master cylinder. I have the factory KH discs up front and the factory 10" rear drums in the rear. I want to keep this setup, but, just change the master and lines up front. Has anyone done this change? What all did you have to change and what parts did you have to use. I have all the stock '66 disc lines and valves/blocks, and I also have a '67 disc proportioning valve and lines to do the conversion if that works easier. Does anyone make a line conversion kit for this type of changeover? I want it to look very stock in appearance if possible, so, I'm going to use a 4 bolt cast iron master. I've seen all kinds of conversion kits, but, none that seem to use factory masters, proportioning valves, and junction blocks. Thanks for your input.