Over the Counter Zinc Additive

Thanks for the input guys. I'm aware of plenty of good oils with zinc in it. Unfortunately, my dad is set in his ways and already has a bunch of cheap oil he insists on using. I don't blame him. That's why I asked for a locally purchase-able additive he can obtain at his parts house. Looks like the Rislone and the Lucas additive is available at autozone and Oreilly. I'll pass along the info. Thanks again.