Thanks for the ones that gave me a answer. I used to read this board all the time, but I cant seem to find enough time to do it as much now.
I thought it was group 4 but I didnt know when they"changed" there formula if they changed the grouping of the oil.
I am a huge M1 guy, its all I use. He was stating how he thinks Shell Rottela Syhthetic is the only 100% synthetic on the market.
I was looking on the Mobil web site but couldnt find anything about it.