Ok, well you have a carb adapted to the intake right? Is it still the PI intake? A trick to fill the motor up and keep almost all air bubbles out of the coolant system is to remove a temp sensor out of the intake crossover and fill the radiator while the sensor is out. The sensor is the highest point of the coolant system so all the air should exit that port. When coolant gets right to the top of that sensor bung, stop filling, wipe up any overflow, put a thin coating of black or copper RTV on the sensor threads and screw it back in. You don't need to go "He-Man" tight on the sensor as it is going into aluminum. After that, give the RTV an hour or so to cure and then fire the motor up with the rad cap off. Squeeze the main top coolant hose as the car runs and that should "burp" the rest of the air out of the system if there is any. And make damn sure there aren't any kinked lines although the only ones that really could are the heater core lines.
2000 Mustang GT Steeda build #48. Bolt ons, suspension, Novi 2000.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.