[DeTomaso] brass ring under thermostat needed or not

[LEVITT1946 at aol.com]

Hello Friends ,
 
I have been battling hi engine temps since I have owned my car.
 
On the open road the car water temp stays steady at about 180. As soon as I 
 pull off the highway , drive in stop and go, etc....the car starts to heat 
up .  About 7 to 8 minutes later the car approaches 240 +. unless the car 
is moving  and the hi temp backs down .
 
I am thinking of removing the brass ring below the thermostat . 
 
I just want to know if anyone has ever done this and does it benefit the  
engine? 
 
I always hear people here say their cars can run all day in the desert and  
the water temp hardly moves if any. I am looking to do the same. 
 
I am going to change the thermostat today to one I just received from  
Dennis Quella. I currently have a 160 thermostat and have had robert shaw 180  
(333-180) in the past and both operate exactly the same.
 
I open the fluidyne petcock and no air comes out. It is always a steady  
flow of anjtifreeze.
 
I also have a 13 lb pressure tank cap .  
 
I also have noticed that at idle my voltage at the battery 12.5 to 13v  . 
raise the idle to 2000 and the voltage moves to 13.75 to 14.
 
I changed the voltage regulator and no change. I have extra grounds and  
even grounded the voltage regulator directly.
 
I am open for any and all ideas.
 
Best,
 
Bob Levitt