170 temp issue revisited

Maybe a month or so ago I posted an issue with a 170 overheat. I would like to bring this back to the table and get input.
After running the tractor for 5 minutes or so the temp gauge creeps up into the low area of red and stays there. I have used a temp gun across the engine to find that it is running considerably warmer near the temp sender than the rest of the engine.
I must inform that the tractor has a recored radiator, new water pump, 160-degree thermostat, new temp gauge and sender. And after all this it still does it. So I've concluded either I have a crappy water pump, a coolant jacket blockage, or possible ignition problem. So over the weekend I did plugs, points, cap & rotor and re-time engine to spec. Hey the tractor runs great but still does the same thing.
The block is nice and cool the head is considerably warmer and the exhaust manifold temperature is in my opinion way too high for a tractor at idle( well into the 400 degree range). Being this engine is set up for an electric gauge you can't just throw a mechanical style in it without drilling it for larger pipe. I have picked up a VDO electrical temp gauge and sender and I'm going to try that just to confirm. I've also replaced the cap but I don't recall popping the cap while warm to see if there was any pressure. So something else I need to check.

I've been a heavy equipment technician for almost 20 years and this is one of the few times I have lost my cool if you will. Any thoughts folks?

Block is 138-140 at bottom
Top of block 158
Thermostat 162 in front and after is 180+. 190-195 at sensor
Ex manifold 480_532.

Back of cylinder head manifold side. I fear I may have to tear this down for a blockage

Its the temp sensor location, that's the problem.  I have a D-10III and a D12III that have it in the back, and both are like 40 degrees cooler than the sensor says.  On my D15II, the sender is accurate, and located in the thermostat housing area.  There may have been a older block installed in the tractor, I think new blocks have it in the better spot.  Also takes a longer gauge and tube, to reach that far...

Thermostat installed correctly? Some can still be installed upside down.

SteveM C/IL wrote: whats the infrared gun say?

Thermostat installed correctly. It has that goofy brass ring so you can't put it upside down but I did think of that. All hoses are new and so is fan belt and tensioned, not loose at all. Guys, I really do appreciate your input and I mean that. But after all this... still a stalemate. Tomorrow I'm going to play with it some more willing I have the time

Going to try to run it tomorrow and get it up to where it normally sits. Then it's time to pop the radiator cap. No pressure tells me we have a crappy water pump or cap. Disagree? Cap shouldn't do this!