I think the zinc was/is primarily for engines with flat tappet cams (which your car has) but I don't think it needs a lot. In my flat tappet engines I generally use a product designed (or at least that is what they say) for older vehicles which I believe has some zinc in it.
You'll have to forgive me for asking, but what does "flat tappet cam" mean? I know I have solid ( non hydraulic) valve lifters that need periodic adjustment, but I really don't understand what a flat tappet cam is. Can you help? Thanks.
