Having been born and raised in Pa. Pennzoil and Quaker State has always been the chosen oil for 3 generations. Except for my 1996 F-150 I had since new only used Bottle Motorcraft for 215,000 miles. Maybe Johnny can explain Pennzoil's famous Z-7 additive package and why it works so well. Is Quaker State a seperate Researched and developed oil by itself?