Using zinc on steel has been done for at least 70 years, it's called galvanizing. The zinc corrodes instead of the steel.
Flame spraying of zinc, aluminum, or a zinc/aluminum mixture is very successful in preventing corrosion to steel.
I have a friend who at one time had a '50 Merc that was reported too have been built with a galvanized steel body as an experiment by FoMoCo.
The problem with galvanizing is getting paint to stick to it. The zinc forms a very thin layer of zinc oxide which must be removed or the paint will slide off in sheets at some point.
A good film of paint is supposed to prevent corrosion. If you get all the rust off underneath it and put it on properly, it'll last a long time.
Rust has at least two forms, the oxidation progresses with time. Rust converter pushes the oxidation process to its final stable form, then puts a layer of paint over it.
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