Hi Derek, There is no substitute for safety, so I applaud your decision to upgrade to a dual reservoir master cylinder. The drum/drum combination valves, simply has the front metering valve disabled, the same as the disc/disc combination valves, and the disc/disc combination valve will work in its place. For your setup you could simply run your front line to a splitter to go to each wheel and put an adjustable proportioning valve on the rear brake line, and leave out the combination valve entirely, I'll attach a couple links to metering blocks that simply join the splitter to the rear proportioning valve, some also include pressure switches to operate brake lights. On drum brakes you do need to maintain 10psi of residual pressure in the lines, from the factory the master cylinder had a check valve in the line port. With a new dual reservoir master cylinder it may or may not have check valves in the ports, so I always drop a couple of 10psi residual pressure valves in the lines to the front and rear DRUM brakes. Disc brakes only use 2psi of residual pressure and if the Master Cylinder is mounted high on the firewall, the weight of the fluid in the lines produces the required 2psi of residual pressure. Here is a link to one source for a residual pressure valve: www.speedwaymotors.com/Wilwood-260-13784-Red-10-PSI-Residual-Pressure-Valve-with-Fittings,233816.html The SSBC proportioning valve you listed will work well and here a few links to proportioning valves I have used: www.speedwaymotors.com/Adjustable-Proportioning-Blocks-With-Brake-Light-Switch,6160.html www.speedwaymotors.com/Wilwood-260-11179-Adjustable-Proportioning-Block,41747.html www.speedwaymotors.com/Speedway-Compact-Adjustable-Brake-Proportioning-Valve,1979.html www.speedwaymotors.com/Adjustable-Proportioning-Valve-Block-Brake-Distribution-System,66525.html Wrench Safe, Mark Classic Car Restoration Club Video Membership

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Twist them together then insert in switch

Hi Carl, While it is true that most aftermarket conversion kits use a GM style proportioning valve, The fundamental function f the combination valve remains the same regardless of the year make and model. So what is different? As mentioned in the video the combination valve includes a metering valve for front disc brakes and a proportioning valve to the rear brakes. The proportioning valve ONLY comes into play during hard or panic braking. It prevents a surge of fluid from rapidly reaching the rear brakes that would otherwise result in locking up the rear brakes and put the rear in skid causing a loss of control. The proportioning valve is tuned to the vehicles braking system as larger and heavier cars are less prone to lock up the rear brakes, while lighter cars can easily lock up the rear brakes. It is best to use a proportioning valve from a vehicle with similar size and brake system, otherwise an adjustable proportioning valve is a good alternative. The metering valve to the front brakes comes into play during normal braking, it is only present in front disc brake cars and prevents the car's front end from diving as the brakes are applied in NORMAL braking. Bottomline: Ford, GM & MoPar proportioning valves can interchange ... but pay attention to the size of the car they are from and they have similar braking systems (i.e. drum/drum, disc/drum, disc/disc). Mark Classic Car Restoration Club

You have no idea how much this helps! Thank You so very much!!!!!!!

Hi Rob, The switch is simply a brass rod with a notch out of it. HOW IT WORKS: The brass rod shifts position if either the front or rear brake circuits lose pressure. A steel pin in the combination valve that is wired to the dash brake warning light is then grounded and completes the circuit and turns on the light. When bleeding the brakes the rod can shift also, that is why it's a good idea to remove the wired steel pin and replace it with a warning switch centering tool while bleeding the brakes. Here's a link to one source for the tool: www.speedwaymotors.com/Speedway-PV2-PV4-Proportioning-Valve-Bleeder-Tool,296895.html and here's a link with Bob Wilson demonstrating how to rebuild a combination valve: www.classiccarrestorationclub.com/video/proportioning-valve-rebuild-011335 Mark Classic Car Restoration Club