[rotorwrench]

An old Ford adjustable wrench will generally work to loosen the governor. I know its a tight fit in there on Ford cars since there is no removable floor panel like the Mercs have but I would think that it still could be removed without all that trouble unless it's a convertible X-frame. The governor is aimed at an upward angle which should help with the cross member but I don't know about the floor. Ford car tunnels are a bit small. It might be easier to clean it off and try to get the screws out that hold the cap.

If it's that much trouble then a test light would make more sense. Attach a jumper lead to a convenient power terminal or the hot side of the battery and connect the test lamp to that jumper with the other side jumpered to the governor switch wire or terminal. Run the car up to on speed and the light should come on. It will go out at a slightly lesser speed when decelerating. That would confirm governor switch function anyway. Repairs might be another matter if required.