hayhauler71,
There is a lot of information available on this subject. I think if you look around you will find that any off-the-shelf, quality motor oil has all the protection needed for most engines.
A new engine running high pressure valve springs coupled with a new cam and lifters (flat) is the perfect candidate for a oil with increaesed levels of zinc. The critical area targeted by the anti-wear properties of the zinc is the extreme load/scuff area between cam lobe and lifter.
This cam lobe/lifter interface becomes less critical with stock valve spring pressures and surfaces that have been run in and worn from use. Unless highly modified, a Stovebolt six would never need the added protection of increased zinc levels.
This is how I see it, but I'm not a professional mechanic.
Stuart
