Keith, I have read this request several times and walked back & forth to my 67 and cannot find anything to measure that matches up to your request (11/2/66 built San Jose coupe).
Possible that the ground screw point is different on my example or that other items in place on yours are not in place on mine. Mine is mostly apart though I have been test-fitting underdash items like wiring harness, wiper assy, heater/AC system, steering column "wired" into temporary position and the likes, for a dry-run before I paint. So basically, mine doesn't have the pedal assy in but I have the cluster out of the way and access to the support brace I think you need a measurement from.
!'ve measured, with a tape measure hooked, centered above the support brace, somewhat diagonally down to the center of where the cluster would mount on the metal dash frame (between the speedo & tach [or other gauges on non-tach cars]) and come up with 7-1/4 inches.
It will be late evening before I can get you any other measurements, maybe tommorrow. Try taking a picture with your ruler of what you are asking so we can duplicate our efforts. (without errors)
