I don't like the Amsoil jokes guys.
Jiao/TS - thanks for the posts. The last one from Jiao is the kicker. Any, even 1/2-a$$ed oil can meet the performance portions of SL => SM, yet some (group 1, 2) oil manufacturers are sweating BB's about SM. What does that tell you about "API" "specs" for motor oil?
Yes Schmoe, SM started out mainly a P reduction exercise, driven by bureaucracy, not engine science.