OK here are the measurements:
Bottom of frame front cross tube to ground : 17.2 cms
Bottom of bottom chassis flange to ground: 16 cms
Bottom of sump to ground: 12.5 cms
Bottom of gearbox crossmember to ground: 9.5 cms
The 6 inch figure given by John above equates to 15.24 cms , so is obviously the chassis to ground clearance figure , not the lowest point.
To the best of my knowledge my car is standard with respect to the chassis and engine mountings, so I would expect these figures to be typical (but we all know just how much things can vary!)
