zinc oil useage?

Or Valvoline VR1, Amsoil, Redline, Mobil1 15W-50. There are several available with lots of ZDDP to protect flat tappet cams. You just might have to put a little more effort into finding them as they might not always be found at parts stores or big boxes.
Royal Purple HPS (HI performance street) has extra zddp in it. I run it in my Harleys.