Big block cooling question

So I have 383 in my valiant and I am having cooling issues when sitting at too many stop lights gets up to 220 I have a new aluminum water pump,new aluminum 2 core radiator with 1" tubes I have a 165 degree thermostat
I've tried a 195 that made it worse so my question is I put a under drive pulley that is 5"in diameter and my aluminum water pump pulley is 6.5"in diameter will that make my antifreeze circulate to slow to cool. any ideas would be appreciated thanks
What size is your radiator core? Can we assume it is a 26 inch core?
Pulley ratio is critical to cooling system performance.
If you do alot of slow speed cruz'n, stop and go and/or have a overdrive trans you must at least drive the water pump at 1:1 I have over driven big blocks in the past with good results. Even my current 340 pulley setup is over driven.