I have completed a rebuild of the heater core on my Second series 1955. Deluxe controls. I have reviewed lots of posts about the heaters to pick up tips for the install. The problem I have is what was missing from PO messing around. In the "chamber" that the heater core was in, a piece of heater hose did a fancy loop sort of and then exited to the engine room. There was no "valve" or anything inside this chamber. Reading here and looking at parts sellers web sites it appears I should have a valve which operates with a cable. Also I see lots of discussion about Ronco valves. What should I have inside the heater core area? Appreciate your help. Regards Doug