Quote Originally Posted by 34_40 View Post
. The cast iron will probably outlive me and most of my family. But like you I'm wondering what's at the bottom of my block and will have to investigate.
Might be time to pull those Loc Tite covered pipe plugs and it will be a good time to install petcocks. The drains on a Ford are just below spark plugs 1 and 8.

As far as some space in the radiator tank - I would imagine that there is some built in for heated water expansion as you don't really want to lift that radiator cap every time you shut that iron engine down, putting water/coolant at over the atmospheric boiling point into the recovery tank - it becomes steam and will escape. A 15 psig cap moves the boiling point at sea level to close to 250*F