I use it in my 2000 Buick 3.8L SC V6 well, actually a 50-50 blend of Amsoil 10W40 and the series 3000 5W30. I was using the 10W30 but had a slight valve clatter when hot and decided a slightly higher viscosity would help, thus the 7 1/2 35 so to spaek. It did, eliminated the clatter, mpg the same and UOA fine and seems to do great. Rumor I heard is AJ himself prefers this oil for his own vehicles.