I need some help on my restoration project. I can't find where a temperature gauge would be hooked into the system. One picture I have shows a gauge setting on top of the top hose connection casting. Mounted that way it would protrude through the hood. My casting does not have a hole in it and my hood hasn't any type of opening for that. I have a couple of other manuals and no mention of any type of water sensor is shown. I do have a fitting mounted in the block just under the carb that appears to be threaded with 1/8 NPT. Did a 39 not have a temperature gauge? Any help would be appreciated.