What exactly makes this oil better than most other synthetic oils (m1 0w40)? What additives does it have or lack that the others do or dont have?

 

https://ls1tech.com/forums/search.php?searchid=1231542

read up on a few of those posts, and take a look @ Patman's posts. he's the oil Guru, especially concerning GC 0w30. Basically its a different formulation, GC 0w30 is thinner when cold, but thicker than most w30's when hot. its actual measured viscosity was like 12.02 patman said? putting in in the w40 range. its a better overall oil, and the LSx motors especially seem to like it. Mobil 1 is good oil too, but I'd pick GC over it anyday.