Far better to use an authoritative source for this info:

http://www.mobiloil.com/Search/Search.aspx?site=mobil&output=xml_no_dtd&client=default_frontend&BCL=%2FUSA-English%2FMotorOil&la=en&km=mobiloil&show_km=y&as_q=inurl%3A%2FUSA-English%2FMotorOil&css=mobiloil&filter=0&ie=ISO-8859-1&oe=UTF-8&lr=lang_en&getfields=description&q=zinc&go.x=0&go.y=0

Our engines do not need zinc, they need phosphorous.  Zinc
dialkyldithiophosphate (ZDDP) just happens to be the least expensive and
most effective vehicle for delivering that phosphorous.  Zinc will
damage the catalytic converter, and this damage is the sole reason for
the reduction of ZDDP in the current crop of oils.  Oils with high ZDDP
content are still available for racing and other off-highway use, where
catalytic converters are not used.

Mike

On 12/03/2011 02:28 AM, Scott Daniel - Turbovans wrote:
> I personally can not say how much high zinc formulation oil can harm or not
> harm a cat,
> but I bet the affect is very minimal on the cat ....just my hunch.