I learned a VERY EXPENSIVE lesson. I was lucky my father bailed me out by paying the diff to get the car running again....with the agreement i would sell it as fast as I could....and did and forgot expensive British cars on a High School budget.....had to stick with my 74 Datsun truck after that.I remember those days very well. I even remember when Mobil Corp made National news with their synthetic/25000 mile claim. I also remember, sometime later, news of engine failures associated with their product..I never used it back then. I just grabbed whatever was cheaper for my burner.