Search feature answered 90% of my questions...but still have a couple more.
My 6.9 was running hot...3 miles from home (5 minutes idle/5 minutes driving) the temp gauge would max out at HOT. I know the factory gauges aren't alwasy accurate...but the radiator was already HOT. Pop the radiator cap and the pressure releases...and no water movement. There was still no water movement at ANY time...even after an hour of running.

Last night i did the water pump.
Flushed everything with the garden hose...engine has no obstructions and the radiator flushed very well. Neither components seem to be clogged at all.
Pulled the old thermostat...replaced with a Carquest thermostat. There seems to be some hatred for the parts store t-stats. What's the big deal? I have come to rely on Carquest parts because NAPA (Need Another Part Again) parts ALWAYS fail on me. Autozone and Advanced Auto have failed as well. Carquest parts haven't left me stranded anywhere.
Installed the new water pump hassle-free. I didn't install a new fan clutch yet. It comes in tomorrow.
Judging from the color and "gunk" from the anti-free...i'd say the thermostat wasn't opening all the way. I can't say it was stuck closed because water MUST have been passing a little bit. Whenever the radiator cap was opened-nothing spewed out.
I ran the truck today. Idled for 20 minutes, and then drove for 40 minutes with the radiator cap off. I drove it hard too-to try and heat the motor up. The temperature gauge got to half-way and has stayed there the whole time. The radiator was hot by the upper hose. My concern is the lack of water movement. There seems to be VERY little to no movement. From what i've read-tis is normal becuase the upper hose and cap hole are on opposite sides. Because the water isn't moving enough to notice any movement...revving the motor has no changes in movement.
Air Bleed Ball in thermostat housing was cleaned and shot with compressed air. It was moving freely.
I didn't use any special anti-freezes...just tap water and some green anti-free. There was mention to use only Low-silicate green anti-freeze and some special SCA's to prevent cavitation.

 

Put your old thermostat in a pot and heat it up and see if it opens before the water boils.
As far as carquest stats there has been lots of reports about aftermarket stats failing so I always went with oem as for or be stranded on the road. the price I don't want to change it again.
With your radiator cap loose it cant build up pressure so it won't get hot, how does it do with the cap on tight.

 

Actually the thermostat should come from Ford or International only.

Last price I heard was 25 dollars.

 

I know the thermostat should be Ford or International...but what's the difference? I always use FTE's advice and especially appreciate the advice of some specific members, but the Ford and IHC dealers were going to be closing and I knew i had a long night ahead of me. I also appreciate the price of quality parts. I'm not a firm believer in "better things cost more" but i know quality parts do cost more. I am careful of many things that cost a lot and are still inferior. It is MUCH more important to pay an extra few bucks for a part that will prevent getting stranded at midnight on the side of some road!
I ran the truck hard all day today...temp gauge never crested half way. I opened the radiator cap many times today to see if i had circulation-i did because the water was hot and the temp gauge was happily below halfway. I suppose i shouldn't worry too much about water movement.
Now that i'm fairly confident the cooling issues are solved...i'll go ahead and get the Ford/IHC thermostat. I'll also add the correct anti-freeze and water mixture. For clarity about the anti freeze; just plain old green and then buy some SCA additives?

 

When I read the posts about thermostats in here what I see is 90% of the users that install parts house thermostats have problems with either overheating or don't warm up to operating temp.

However that leaves 10% that have used them with success.

Ford and IH thermostats have a rubber gasket around the outside of the housing and no internal bypass.

Most parts house thermostats have internal bypasses, and no gasket.

Also when users install the Ford or IH thermostat, problems run in the less than 1% range.


My logic works like this,
5 dollars at a parts house with a 90% chance of problems.
25 dollars at Ford with a 1% chance of problems.

If I have to change it again, the Ford thermostat was cheaper since I do value my time and wasted antifreeze that I spilled.

Anymore I use Fleetcharge with SCA pre mixed Heavy Duty Antifreeze from NAPA and distilled water or the pre diluted version of the antifreeze.

FCA 003 or FCA 007 are the NAPA numbers.
The higher price one is full strength, the lower is prediluted, both have SCA premixed.
Purple in color.

 

So...i'll be stopping by the Ford or IHC dealer first thing on Monday.
Looks like i already fit the category of failing theromstats...seems like right off the bat the truck won't even warm up to operating temp.
The Carquest thermostat i got did come with a rubber gasket on the outside, and also has an internal bypass.
But the thermostat i pulled from the motor did not have a rubber gasket, so i took the rubber gasket off the new one before installing (to match what was pulled).
Being that the thermostat that was installed in the motor did not have a rubber gasket and did not have an internal bypass leads me to believe it was either a failed generic unit or an original with 170k and 4 years of sitting behind the PO's shed.
At any rate-i will do as i should have in the first place and install a Ford/IHC unit.