If its not in your oil then it's probably not the head gasket. How about your waterpump? Also check the coolant elbows make sure they aren't leaking. There's usually something else bad when the head gaskets go on these motors.

How white of a smoke is it? Is it blueish? Is really thick white like you can't see behind you? A little white smoke is normal especially in these colder months. How long ago did you do the lim gaskets? Did you put rtv on the corners of the block when you did them?