Just rebuilt a 455 and got a couple hundred miles on the motor. I put an edelbrock package on it so I have the aluminum heads and intake. Now after driving it for a little while I have to add about a quart of fluid to the radiator after a 30 minute drive. I have an overflow but the fluid never pulls from the reservoir. I have a pretty heavy hose on the overflow as well as I have blown air through the line and reservoir. This leads me to were else the fluid could be going. I keep an eye on the fluids on the car and the radiator fluid is clear and clean. The oil is also clear. I have also parked the car and kept an eye on the ground with no luck. Any suggestions?

Another note: with the aluminum intake I received 2 slugs that are to be put in when the intake doesn't match up with the holes on the block. These were not put in due to all ports matched up.

 

If you're sure the coolant isn't leaking out a crack or loose hose or bad cap, then it's going into the engine. Could be bad intake gasket, bad head gasket, or a crack that only opens up when the engine is hot.

The two plugs are not for "mismatched" ports. They are to block the heat riser under the carb if you choose to do so.