I just went from a 10w40 to Mobil 1 20w50 and I noticed a difference in the feel and sound of my shifts...taking into account for being anal and having papers certifying my status of basket case, there was a difference...I am now going to stay with the Mobil 1...THIS is NOT another oil thread, just an observation : )

06 America, debaffled pipes, modified box, 132 jets, 1 shim