/6 temp sending unit
I had the same prob as you from down here in Australia.
Your '63 has a different temp sender to the other years.
I forget now which one I used, but Dan The Man set me straight.
He actually even bought me one and shipped it Downunder for me at cost.
I'm sure that he won't mind a PM from you, username:
slantsixdan
He knows it all
Hope that helps