I have a question regarding the metal tube used in the heater hose line on the later KFs. Most pictures of '51 - '55 KF engines I see have this metal tube connected to the water pump, running the length of the engine and then a short hose from the end to the heater. If you double-click on and enlarge the picture I posted you can see the tube (the picture is not my engine). My '51 Special does not have it. I've also see pictures of other '51 Kaisers that do not have it but most I see do. I've checked the parts book, shop manual and KFOC Handbook but can find no mention or picture of it (my '51 Parts book is not illustrated but still nothing in it sounds like this). Anyone have any information on this part or when it was introduced? I know my '51 Special is an early one with no stainless rub molding at all and no bright work around the windshields.
Addendum - thanks to Jim B's parts manuals online, I found it! It's number 1 on the other attached screenshot from the 1951 illustrated parts book. It is part of the heater (AC) package and listed as 208228,Tube-temperature control valve to engine.
So, does anyone know if there were "early" and "late" versions of the heater package?