Hi,
Except for dual pipes I have a stock 221 in my 41 convert. On a regular Melbourne (say 24C) day the stock temp gauge will move to 3/4 hot on a regular drive. This is after I had re-cored the radiator, installed new water pumps and 'flushed' the block (albeit with a garden hose).
The car was without thermostats, so I wound up installing 160 deg thermostats and capillary SW oil and temp gauges. I consider the stock units questionable due to age of sender unit.
With 3/4 hot on the stock temp gauge, the SW unit shows 160 and stays there except in heavy bumper to bumper traffic. An IR thermometer backs this up.
Your radiator looks low. Sure it is equivalent to stock? My radiator is 4" thick, 22" wide and 21" high not including top and bottom tanks.
What fan are you running? I have a 6 blade (3 large blades 3 small) fan on the crankshaft, and no cooling shroud.
Just on the aftermarket guages, my stock oil pressure reading was 5 PSI. The aftermarket SW capillary reads 30-40. A tired stock sender unit I expect.