I suspect that you are checking your glow Plugs from a different view than most of us would.
This site has a step by step pictorial you need to scroll down the page to see it:
http://www.dieselgiant.com/glowplugrepair.htm
For more stuff:
http://www.dieselgiant.com/mercedes_diesel_maintenance_tips.htm
I think the Mercedes Engine might be to heavy for a Hudson.
When I was 10 years old I crossed the street with out looking (I was involved in a rock fight with another kid) and was hit by a Hudson. I still have a slight crease on my left hip where the bumper hit me. The Doc said it separated a muscle in that area.