Hi Dan. If you’re talking to me, I installed a Powermaster 100/125/150amp Smooth style one wire in black (case, fan, and pulley).
If you’re not talking to me, oooops my bad! 
I searched about the current radiator and there is something I discovered.
The radiator is 3 core and was recored, after that run 4000mile til now, and one more thing the current fan is half in/half out.
Thank you for telling me your opinion!
I would search those parts
I purchased the infrared thermometer today, so would measure the temperature of those hoses.
If my understanding is correct, runs 170℉(80℃) upper hose and 150℉(65℃) lower hose with car temp gauge around 1/2 as an estimate in case the correct thermostat is put in?
I might need an electric fan, especially in Japan…
170 deg is too cool to be reading 1/2 on your dash gauge. Either the thermostat wasn’t fully open yet, or your dash gauge is reading wrong. Measure the hose temps again after you’ve driven for awhile.
Edit - it is also possible you have a 160 deg thermostat, but if that is true and it was open, you are not getting a 30 deg drop across the radiator.
Bottom line, before I spent all the money on going to electric fan and alternator upgrade, I would put the correct RobertShaw 190 deg thermostat in. Since you already have a 3-core radiator, that might just fix your problem.
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The gauge temp is based on the temperature at the sender. So check the temperature at the sender. It may be closer to the expected 190 degrees. For some reason people think that a lower temperature thermostat will eliminate overheating so they put in a cooler thermostat. Because the available senders are not consistent with the original some restorers actually bend the needle to make it look correct. You can test the gauge and see if it is accurate. You need to replace the sender with a 23 ohm resistor to make the gauge read in the center.
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Following this thread is saying the car does not have an overheating issue , it has an airflow issue !
If the rad was recored , was it done with a core with a high fin count ? They can effectively block air flow , especially with multi rows. The distance between the ac condenser and the rad also plays here . Does the car have a coolant recovery system . Important to keep the air out of the system . Did the car puke coolant or just get hot? All these are important to fiw what you have
Before throwing a bunch of cash at it , id do the correct thermostat ,coolant,coolant overflow system, and maybe the rubber dam that goes across the core support to try to get the airflow thru the radiator … And dont forget the rad cap for every pound of pressure the cap has , you get 2 to 3 degrees more temp before boiling . A 13lb cap will get you to almost 250 before boiling ( without air in the system). My .02 worth
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The alternator was upgraded before car delivery because a shop where I purchased that Cougar installed AC.
Thank you so much for the helpful advice.
I couldn’t get the detail of rebuilding engine, so first of all, I would like to check the temp of hoses.
Incidentally, when I took a photo of alternator, there was something that caught my attention.
Is this the coolant temp location?
Thank you for helping.
I got it, I will check the sender too.
If the correct thermostat is installed, doesn’t the needle of dash gauge mark a red zone even in hot weather?
If my memory is correct , that is a temp operated vacuum switch that was origionally plumbed with ported vacuum, manifold vacuum and the vacuum advance. If the engine temp got hot , the switch applied manifold vacuum at low speed or idle to increase idle/fan speed. Might want to hook it back up
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Thanks to everyone, my Cougar has the coolant recovery system that is working correctly.
Thank you for letting me know.
Is this vacuum advance temperature?
Mine isn’t connected to anywhere! Is it OK?
If im thinking right , if thr vac switvh is still good ,at normal temp , the distributor vacuum advance would be ported vacuum…no vac advance at idle
When temp goes up the distributor sees manifold vacuum which should speed up idle speed (both fan and water pump) helping to cool the engine down at slow speed. A real cheep fix if it works as it should
I keep hearing people repeat that and it isn’t true. While the carburetor has very little vacuum at idle, it does have some and enough that the engine idle speed picks up a lot when the vacuum hose is connected. I must have read this one million times. It still is not true.
Yes, that is the temp controlled vacuum switch and it works as you described. It advances idle speed in case of overheating.
Royce, you’ve convinced me that ported vacuum can be non zero at idle since they tell you to disconnect ported vacuum to the distributor vacuum advance when setting timing.
So if ported vacuum is advancing the timing, then disconnecting that vacuum will retard timing decreasing idle speed. I’ve never seen that happen at idle on a small block, but am sure you are right.
Disconnecting manifold vacuum from the retard side of dual diaphragm distributors will advance timing causing idle speed to increase.
True, I have a golf tee in my timing light box to plug that hose off. Funny they tell you to plug the hose with no vacuum!
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Ah! It’s the device for carburetor engine!
Ex owner was using PerTronix ignitor and it is currently the same.
Probably he knows what thermostat is installed, I wish he was here😂
Progress report
I went to drive in order to measure water temp today.
It run 197℉ upper hose and 181℉ deg lower hose with car temp gauge around 3/4, and run 203℉ sender.
After that, drove around a town repeated doing stop and go.
I founded out that the water temp didn’t rise a red zone by putting the sifter P.
Is there something wrong with car temp gauge?
203 deg at the sender is a pretty normal operating temp, so your gauge and/or sender might be reading a little too high. My dash gauge doesn’t read 3/4 until temp sender is 230 deg, top hose is 225 and bottom hose is 195.
But, only 16 degrees drop across radiator is not normal. When my 70 351C sender temp is 205 deg, top hose is 195, and bottom hose is 165.
Shifting to P increases idle speed just enough for your fan to cool better.
My temp sender measures 30 ohms to ground at 205 deg which should read a little below 1/2 on the dash gauge.
You can check gauge calibration with one of these handy devices:
https://desertclassicparts.com/product-category/gauge-testers/
Has anyone checked the initial timmig…not wit a light but with a vacuum gauge ?
Plug the vac advance and put gauge on manifold vacuum. Slowly advance the disributor until the vacuum gauge stops increasing. Lock the dist down and let the engine heat soak fo 10 minutes. Try to start…if bogs when starting, retard the timming a few degrees and repeat
When it starts withot bogging , your done. Reconnect all the vacuum hoses