Frozen float bowl drain screw ?

Heat the screw. The idea behind it is to break the corrosion bond, not expand the metal.

Nessism, It worked !!! The mistake I was making was also trying to use a large blade screwdriver instead of a good set of channel locks. Carefully grabbed the outer edge of the head of the screw, squeezed the plier handles hard, and carefully turned screw out. Worked like a charm. Now to continue on with the rebuild. Thank You to "All" that responded to my post.