Thanks a bundle. If the pressure is under these figures I am guessing that the best procedure would be to replace vacuum hose to regulator, the regulator and possibly the high pressure pump. If I found the schrader valve, which it seems Ford was trying to hide, I think I can find the regulator.
Also, a word of caution. My two former auto advisors were my brother and, following him, my brother-in-law, both of whom have passed on. But, if you reach their age, which I pray you do, you will be an old man like me.
Again, thanks a million, you do a great service. This old truch has taken me and my family across the country many times.