308 overheating problem

I have a 1985 308 QV ( a usa model ) with an overheating problem. The temperature gets up to 220 to 250 depending on the temperature outside. Both of the fans are comming on and is turning the right way ( pushing air into the radiator) the fans are comming on at 190 degres.
I have removed the radiator and had it rotted out twice.
I have replaced the thermostat and doubled checked it with boiling it to see when it opens. ( opening up at 180 degres )
I have replaced the temperature sending unit and had the water gauge calibrated with each other.
I have replaced the water pump and just removed it to double check that it is working good. ( I have noticed that the new pump came with a plastic propeller instead of a brass one but not sure if that has anything to do with my problem )
I have replaced the radiator cap with one that opens up at 16 LBS ( 1.1 Bar as O.E. )
I have pressured flush and back flushed the whole system and bleed the system two different ways one was with the front end up in the air so the radiator bleeder is the highest point of the car, and the other way was with a hose running from the radiator bleeder to the expansion tank so all the air was out and solid fluid was the only thing running through the hose. and found no air in the system
I have pressure tested the system for leaks and found none
I have replace all water hoses
I have checked the mixture at the tailpipe and it's correct.
I have also block tested the engine for a blown head gasket and I also checked the system with my gas analizer to see if I had any co / hc comming out and found nothing.
The customer just stopped by to look at the car and he informed me that the radiator had a tag on that it had been recored before he purched the car. I was also wondering if anyone out here has any idea how many rows or thickness an O.E. Radiator has.


Thank you in advance for any help you can give me in this problem.
Glenn

I would put a stick thermometer in the top of the expansion tank with the cap off. I would run the car and check all the temps and compare it to the gauge inside. My fans kick on at 195 at the tank it was 200. I was having the same probelms an it was a guage sending unit issue.

Oh collabrate the stick T by puting it in a glass of ice water and amking sure it read 32 degrees.
It may be a bad wire between the sending unit the the gauage.
Kelly

pretty far out idea, but are the vanes on the plastic impeller slanted the correct way?(rotation) I have never seen a plastic impeller on a car water pump. But, it sounds like you have one. On counter rotation boat engines, one pump is made to turn the opposite direction with the impeller vanes pointing the other way. Just a thought!.

Glen, is your car still overheating?