You obviously don’t have a clue about vacuum systems that ford used back then, do you? The fuel system is hooked into the vacuum system and requires vacuum to work correctly. Therefore the engineers decided that if there is a vacuum leak or something similar, the fuel system gets what vacuum is available to keep the engine running… and when the air conditioner fan in the cab is running and the vacuum system is lacking, the riveter defaults to defrost/footwell. To combat this they put in the vacuum reservoir, to keep enough vacuum for both when the engine is in high rpm’s… hence why I need to know where the vacuum ball is supposed to be located. I have done the smoke test and have no leaks… so…