I used mobil 1 once, and won't use it again. I put it in one of my vehicles switching from castrol, and noticed that the more and harder I drove the car, the less oil pressure it would have when it was hot. The oil started to foam up when this was happening, which is why it had the loss of oil pressure. Changed that **** a week later, and went back to castrol gtx with no problems.

In my race cars, I use the valvoline non synthetic racing oil with the lucas. I put royal purple in my cobra. And my regular drive around cars get castrol gtx.