Does the distance scale on the Speed Graphic (lets say it is set at 10 feet) indicate the distance from the subject to the front of the lens, or from the subject to the ground glass? My rangefinder does not work, so I have been guessing distances on the scale when shooting rapidly without the luxury of a tripod or ground glass focussing. I refuse to go digital or use anything smaller than 4x5. I am just zone focusing. I am thinking of carrying a thin cord or rope 10' long that I can hold to the subject to get exactly a 10' distance. Not knowing if the distance is from subject to front of lens or from subject to ground glass could throw off my focus. I have another camera in 4x5 which was custom made for me with a 75mm Mamiya lens on it. It gives the view of a 24mm lens on a 35mm camera. I also need to know if the same applies to the scale on a lens. Would the scale on the lens indicate the distance from subject to film plane or from subject to the front of the lens? I use this camera, which has a Graflock back, as a zone focus point and shoot, but up close in the 5 to 7 foot distance with lens wide open, focus is critical.

Focusing on all cameras is from the subject to the film (or digital sensor) plane. The ground side of the ground glass should be at the film plane.

The tolerance on film position depth in a film holder for 4x5 is .007 inch.
http://home.earthlink.net/~eahoo/page8/filmhold.html (link).
TriX sheet film is .007 inch thick.

Thank you kind sir ! That makes sense. Does this mean that Tri-X (my favorite is the best sheet film or are others the same?

No, TriX (320) is just an easy to use thickness reference if doing critical measurement and you happen to have some on hand.