I don't know whats been posted about the removal of zinc di alk phosphates since 2007, but I've been doing some research about this and wanted to share what I have found.

Most of this I found from the Mobil 1 website

As of 2007 oil makers are suppose to reduce the amounts of zinc in the oil because its bad for catalytic convertors, oil has a phosphorus additive that is what actually bonds to metal to provide the wear protection, and this phosphorus is added to the oil in the form of ZDDP.

The phosphorus is what protects the metal from what I gather

any oil that has this certification:

GF-4

has reduces amounts of phosphorus (800 parts per million [ppm]or less)

I went to the mobile 1 website, typed in zinc under the search options and in one of the articles a guy was asking a question about the zinc stuff and how is race mustang was showing bearing wear, and the answer included a chart that showed all the oil the company makes that still contain the phosphorus and their ppm (i.e. anything800 ppm or above)

Now, this is my conclusion, so take it with a grain of salt, because I don't really know for a fact, that any oil that does NOT have the GF-4 certification will have higher levels ofphosphorus ppmand will protect olderhydralic flat-tappetcamshafts better than cat safe oils.

And, I'm not singing the praises of any specific oil, but for example purposes, Castrol's Snthetic 20w-50 supposedly has higher levels of the stuff for older cars and it does NOT meet the catalytic converter requirements and also a lot of AMSOIL products contain higher amounts of ZDDP and don't meet the cat requirements. Actually, the last I read, only one of their products met the gov't requirements for cat safe stuff.