Coolant keep blowing out....WHY?

I have a 2004 SVT Cobra and I just installed a Temp gauge and installed the sender in the block. Upon filling it with coolant and running it the radiator keeps blowing coolant from the Radiator....why. I even tired to get the air out of the system via the bleed valve. Is there any special way to bleed this cooling system. I need help! Tell me how to bleed and fill this system?

GLWBEAR