If it worked, why the hell did you change?

My car has been using all 10w-30 standard valvoline, and my engine runs strong... but i feel my timing off just a bit...

Former owner of a 1995 Ford Contour GL w/ 2.0L ATX Proud owner of a 2005 Ford Taurus SE 3.0L V6 Vulcan --Looking for Commodore stuff (Drives, Units, Amiga, games, etc)If anyone has any of this laying around and wants it gone, lemme know --