Burning Coolant?

This past week I've noticed my car was overheating. I opened up the rad and noticed I was down about a half litre of coolant. I topped it up thinking some of it bubbled out. A few days later the same thing happened; temps went up and I was down about a litre of coolant. My car isn't leaking coolant from anywhere so assuming I'm burning it up I went for a drive tonite. I hammered it in second right through the powerband and noticed some white smoke coming out of the tailpipes. I swapped the heads and intake a few months ago and everything was fine up until now. Could this be the intake gasket? I really hope its not a head gasket.

There's no oil in the coolant and theres no coolant in the oil. The amount of coolant I was down was just an estimation. Looking in the radiator the fluid level goes down 3 or 4 inches every few days.

The part that bothers me is the white smoke because I know its being consumed by the engine and not leaking anywhere.

I'm just trying to eliminate the head gasket as the problem. I really don't want to have to tear down the motor again. Is it possible that the intake gasket could be the problem? My oil isn't milky or anything, but could coolant find its way into the combustion chamber via the lower intake?