I have 3 different hoods, one on at the moment is a glass cowl style hood that would not be sealing much at all, it’s on there to hide the twin 950’s on the tunnel ram from the police 🙄 maybe there is something in this because it is all of a sudden a bit hotter than before.
Fans are Ford something and suck like crazy

Update,,,
Purchased a temp gun, ran the car at home up to 210 and had my son shooting all the right spots with the gun, on the brass fitting that the sensor is in, on the front of the ali heads and even let the pressure out of the radiator and checked the temp of the water, 170 was the highest reading we could get while the gauge was showing 210, had already replace the sender so the gauge is *ucked yeah ??

sure looks like it from here ! [i finally got the pair of x-ray glasses from the comic book add i ordered all those years ago to "see through" women's clothing ! :biggrin
without going back through the thread, was that even mentioned to try an IR gun ? that's usually the first thing i do with heat issues.
i'm so dumb sometimes ! and i get dumber the older i get..........

Be aware that the IR temp guns should only be used as an indicator as they need to be calibrated for the surfaces they are reading. being off by 40 degrees is unlikely unless you have a bad gun or heavily coated surfaces.

The only way to know for sure what the temp is doing is to used a thermocouple probe installed a closely as possible to the thermostat housing. The probe is then coupled to a digital meter that will read accurately to a 1/10 of a degree or better. They also respond very quickly. I use this method exclusively when chasing temp issues. One can probably get an entire setup for less than 100.00. A lot of digital volt meters now come with this feature/accessory. You can also buy extensions for the probe lead that will allow you to place the meter in the car so you can watch it as you drive. Also make sure you get the correct probe and extension types as there are two different ones. Type J and Type K. Mixing the probes, leads, meter will skew the readings.

In my testing I have found more than one "name brand" gage to be doing exactly what yours appears to be. It is also typical for them to go farther out of whack the warmer the coolant gets.

then, it can boil down to [yes, pun intended ! ] just how hot is "hot" ?
"hot" to me is 220+ with coolant loss in old stuff, while that temperature in newer vehicles is just running temperature.
with a good cooling system, i would rater see 205-210, than 160-170. but that's just me.
along with the elevated temperature however, the tune MUST be optimized for best results, or bad things WILL happen.
if one doesn't take the effort to do so, or can't for whatever reason, then it's imperative to keep the temps low.
wild swings from idle to cruse need to be looked at because a steady temperature is best.
just my opinion, your mileage may vary.

"over heating" is kinda relative . . . . when the FIRST "Pacific Nationals" (mopars at the strip now) were held in Vegas, in AUGUST, it was HOTTTT outside for sure, think like 110 F in the shade !!! . . . anyhow, I drove my 300Hurst with the AC thumping out cold air, at speed on the highway - was running 205-210 F getting up to 240F at the top of hills, but cooling back down to the 205-210 . . . was not pushing anything out of the rad . . . was factory rad/shroud/t-stat and I had put mechanical temp gauge on the car. Sure it was hot, but no pinging or adverse effects to the old 440 - and NO WAY I was going to NOT use the AC !! . . . .and today - the cars are running at the 205-210 F temps as "normal" . . .

if i understand thermostats correctly, they are not fully open until 10-15 degrees above their rating. in other words, a new car stat coming with a 205 degree rating will not reach full opening until 215-220 degrees.
if i understand heat transfer correctly, the larger the difference in temperatures between the coolant and the surrounding material[s] [the radiator structure], the better the heat transfer, thus the better the cooling system will operate.
back in the day, a common factory T-stat was a 180-195 unit, so it is conceivable it was not fully open until 215 degrees.
i too, used to be a believer in keeping temperatures in the 160-175 degree range, but i have had much better running success utilizing higher temperatures than lower ones, so that is my preference now.
still, there is more to it than just placing a piece of cardboard in front of the radiator to bring the temperature up.

I was there, it was crazy hot on the gravel infield of the race track.

On the cooling, if the car cools back down when you slow down, then most likely it is a water pump or air flow problem. If it will not cool down unless you shut it off and let it cool, it is likely getting air locked. Still a flow problem but caused by trapped air in the system. When I first got my Coronet, it would do that at high speed and not recover, but it had a bad head gasket.

OK guys, got home from work and fitted a new temperature gauge, AutoMeter #4454 ( $360 Aussie FFS ) , car now running at 180 with a 190 maximum @ 3500 rpm on Highway.

YES !!!!!!!!!!!!!!!!

Thanks for your help.

You sound stoked (my best Australian!).

RR ..... we should take up a COLLECTION for our Aussie member .... 360$ for a water temp gauge ??!!

Yes somebody sure came out ahead on that one.

I admire your dedication!

And do agree with FFS, that seems crazy.

Unfortunately not the first time I've seen Autometer with pricing way out of line.

glad it was an easy fix !

Hahahaha, I replaced everything else first .....

i wonder witch guage is bad.

A man with two watches never knows what time it is.

On the other hand, a stopped clock it right twice a day.

The two most common things I find when a car overheats at speed are this.
One lower hose collapsing, and too lean in the fuel. Check the plug color!!