Another quick update and reply
Did you ever change the fuel pressure regulator?
>> Yup, thank you for the recommendation, had that changed with all injectors.
Here is the update:
Mechanic performed another block test. After 30 minutes of waiting, the chemical changed color indicating head gasket. So, this is particularly interesting since he did two block tests earlier, which he said for 5 minutes then 10 minutes and each passed. Once we did a test for 30 minutes than it failed slightly. Imagine my response when he told me that.
So alas, after spending a big $$$ on injectors that may not have been needed, I'm now facing a head gasket swap....which I must do since I don't want to pass this problem down to a future owner.
Will all of this be worth it? I'll be pretty deep $$$ into this pathfinder and not sure what the value will be. If you see the pics, its an extraordinary specimen for the era...but hard to know when to draw the line.
Thanks to everyone contributing perspectives to this thread. Easier when you can share the high's and low's.