[frankym]

Ron61 said it, start by exhausting the usual tricks before you go nuts. 3 small holes (1/8 diam) in the thermostat flange is what I have seen. You have the high speed fan, I presume it's in between the motor and the radiator, so make sure it's pulling air and not pushing it, kinda dumb, but the polarity of the wiring could be backward. Other things to help would include building a shroud or adapting one for your car, channeled air will create a LOT more air flow than just a big fan in the middle. Also, baffling the radiator might help, many of the problems I had with my previous big block was that the water was flowing too fast through the motor and it never got a chance to cool off inside the radiator fins. Never been involved with baffling, but that radiator of yours shouldn't need it. check the fan, make sure it's really 3000cfms by mfg, I had the black magic fan and that thing was a beast, and it was around 3000 cfms, some of these fans are only 1200, so make sure you check with the Mfg. Also, make sure it's switching on in advance of getting too hot and that it's staying on, you should be able to sit in your garage idling. make sure you've bled all the air out of the cooling system too. Your temperature sensor may also lie a little, are you physically overheating, are you boiling over or does the temp gauge just scare the begeesus out of you, sometimes the temperature sensor will lie a little because of its location.