Here's a silly question

[QUOTE='73red-duster]I have used Valvoline for over 35 years,and have had great luck with it. Most of my vehicles have run high mileage,before I got rid of them. (My last truck went 350,000,my current has 200,000). I am thinking about going to Rotella for my a-bodies though,because of the zinc factor that has been discussed so much on here lately. :-k[/QUOTE]


What exactly is the 'Zinc factor?' :read2: