Any suggestions on minimimum content of ZDDP should be for a fairly aggressive solid flat tappet cam and ‘heavy’ valve springs? What’s the maximum level before problems (if any)? The net, where data is available, seems to show oils with ZDDP between 1000 ppm and 2000 ppm. It’s interesting to note that one ‘cam break in’ oil additive brough the level up to 5000ppm. Based in Australia. I have posted this on another forum I read, but a lot of net oil searches lead me to this site. Cheers.