I don't know if I have a flat tappet cam in my engine. I bought it in 2005 and it's a 64 block. No clue as to what the internals are. I don't want to add zinc and have it mess something up. Looks like it has a bit more than conventional Valvoline 10w30, but not way up there.
Using a high-zinc motor oil will never damage an engine. The only things that they can harm are catalytic converters, which shouldn't be an issue for a '70 Monte Carlo.
"When I'm in a slump, I comfort myself by saying if I believe in dinosaurs, then somewhere, they must be believing in me. And if they believe in me, then I can believe in me." - Mookie Wilson
