Dr. B - Thanks for your responses and suggestions, I really appreciate your help. The stuffing box is very normal and just like all the others I have seen. Also there is no special seal or anything on the locking nut. I am careful not to move the the packing nut while tightening but even just to do an experiment for myself, I backed the packing nut so far off so that water was gushing in and then tightened the locking nut and same thing - no water - so even if I did slightly tighten the packing nut - it was so far off that it wouldn't have mattered.
Now where am I supposed to be getting a drip from? Between the packing nut and locking nut or further towards the engine where the shaft enters the packing nut?
Oh and also prior to this change I did observe the correct drip amounts both at rest and with shaft spinning so I know this is not a special stuffing box.