Dual Master Cylinder

My guess is that his older 65 Valiant has the older junction block that can be used with the dual master cylinder like I have been for years. Like you said. Four ports. One goes in and three go out. One to each of the front wheels and one to the rear which goes to a splitter and then to each of the rear wheels. No proportioning valve. Older vehicles didn't even have a sensor to tell you that you had low fluid levels. dodgem