After too long on Edmunds,I found this board!It's great!
I've read all the posts here and am still confused as to which oils are still "full synths" by the Class 4,5 base stock definition.Am I correct that those are Amsoil,Mobil-1,and Red Line?
Are Valvoline,Quaker State,Pennzoil,Chevron and Castrol ONLY available in Class 2,3 or blends of mainly those base oils?