I have a 1999 Chevrolet Corvette (LS1 engine) with 91k miles on it. I drive my car pretty hard with a lot of high RPM use once the oil is over 160F. I live near Detroit, Michigan. The owners’ manual call out 5W30 oil to meet the GM Specification 4718M. My car has used 5W30 Mobil One oil since...
