High-zinc oil or ZDDP oil additives?

So I have a 360 LA block engine from roughly the early to mid seventies in my barracuda. When I first got the car, I threw in some cheap-o $3.99 a quart Napa oil (no, I haven't been driving the car on it) just to have something clean in it while I get the car roadworthy. I will do an oil change before it hits the road for good with something a little nicer, but for now, I'm wondering if I should throw in some zinc oil additives. I know that oil used to have high zinc levels (1200-1400 ppm), and that modern oil has much less. Should I get some additives?