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.
those solid lifters are so work hardened by now thay zinc is probably not mandatory for you. break in yes but after its up and running with stock limp noodle springs its probably ok. check out Rotella diesel oil. iirc it still has zinc in it.
