Steve- the B10 was made at the Zama truck factory so the metallurgy is
superior to later datsuns not to mention that some of them bound for
Europe where partly galvanised (Belgium models?) which was amazing if true.
There seems to be alot of lead content on the paint used so be careful
guys when sanding away.
Deoxidene or industrial Phosphoric acid is great for rust, providing
some rust in deeper sections if scrubbed well with a wire brush and this
acid, you will be able to really remove most, if not all the rust.
Best if possible is to strip your panels of all paint and undercoat and
get them galvanised or electro zincolumed. I did this to my guards and bonnet.