If you have drum brakes all around, it's a distribution block, not a combination valve. Also, unless the line coming from the master cylinder goes STRAIGHT to the rear brakes and does not go into the distribution block, I don't believe you can just put it in the line going TO the distribution block. That would control more than "just" the rear brakes, I believe. It must be in the rear line alone in order to control pressure to the rear. I believe that's correct. If I am mistaken, I will count on my comrades to correct me. Regardless, I would still put it in the rear line, since that's all I would want to control. ......but then as I mentioned earlier, I would use all the factory stuff like I did on mine. Makes it much easier. Good luck with it.