Originally posted by BKL98MK8LSC:
I have read that the base oil is what affects heat carrying capacity. I dont know which is better or for what reasons though. The light oils pump more efficiently and superior volume may carry away more heat. I have no way to test this so its guessing. The 5.0 engine in the picture is using 5w-20! The testing procedure detailed in this link is tuff. I am to stubborn to believe that 5w-20 protects BETTER than a heavier oil. But it does pass their tests.
http://www.mustang50magazine.c...te_engine/index.html