Battling overheating new 360 build

inertia said
This post indicates the cooling system at idle is doing it's job , thermostat temp(ish) coming out top hose , rad dumping enuff heat to cool at idle, pump circulating.
Now, at speed the partial plugged rad could not keep up with the added heat cuz it's effectively too small, and the temp creeps up till the faulty guage makes you uncomfortable.
If you pulled to the side of the road it woulda cooled down.
On top of that your believing a guage you know not accurate.
Does the engine now overheat at speed ? What's the upper rad hose temp in the "overheat" condition, engine still running ?

Engine has been overheating at speed. New rad and 8 vane pump made no change. I was saying the infrared thermometer gives off funny readings, not the dash gauge. What I did find is that the dash is saying I’m almost at H when the infrared therm is reading 200ish, so perhaps that’s where the dash gauge is calibrated from the factory?

Also, this is where my temp sender is tied into the manifold, should I be tapping in closer to the water neck?