And it might continue to thicken!!! I built the car with two seperate master cyls & balance bar along with the Mustang pressure valve in the rear brake line, BUT in the pics that Anthony Prendergast has sent me of the car as purchased from Rod last year there is a photo of the empty engine bay with an extra bracket with three bolt holes that has been added in front of the original Master Cyl positions presumably for the Large master cylinder you mention. The steering column also was modified by removing the upper u-joint & replacing with an angle gear box that used a couple of mini diff side gears, I presume these mods were done to clear the space for the Chev Swap at the time. From what you describe it would appear that when the large single master cyl was fitted the brake lines got re-plumbed in the manner you describe where it worked on all four wheels, that would have made life exciting for Rodney!!!