I personaly think I would stay away from this stuff. I am VERY attentive to how my engine acts and behaves whenever I change something, and it seemed a little more sluggish after I put this stuff in it, a LONG time ago. There was something else that went wrong arounf the time I put it in, but I can't remember what it was. I don't know why anyone would use this stuff when synthetic oil is out there. I used Mobil 1 since the engine had about 30k on it, and when it crapped out at 154k (long story) I had it rebuilt. The builder said my engine looked better than many engines he had seen with less than 30k on them. He said the bearings were still shiny, and everything internaly was fine with the motor. He said it even still had the factory cross hatching on the cylinder walls.