63mako

The point a lot of people are missing is the fact that the new flat tappet grinds have much more aggressive ramp rates and higher lift than they did even 5 years ago. Everybody wants the most power possible out of their build. Adding 1.6 rockers also increases the pressure on the lobes. Fast ramp rates and higher lift produce more power. They also subject the cam lobes to a lot more pressure and require heavier spring rates. The combination of the above and the reduced zink combined is the problem. If you want to pull the most power, go roller. If you won't spring for the extra $ go flat tappet with less radical ramp rates and lower lift but don't expect the big power numbers. There is always a tradeoff.

Surfer69

I use 10W40 Valvoline motorcycle 4 stroke oil which has the highest zinc you'll find on the shelf and it's properties are the same as regular engine oils. I mix this with 10W30 Royal Purple and have had no issues on new flat tappet 1.6 HP cam.

SHAKERATTLEROLL

If you would take the time to look through the link I gave then it will show you with real facts that the new STP does not have the same contents as before.