I spent alot of time researching oils and reading into the testing proceedures. From what I could find. Heck even at PRI I talked to every oil manufacturer there to get Technical Data Sheets on their product. Chemistry is fun

If I could afford it Mobil 1 Racing oil (not off the counter stuff) is extremely stable and is built truely synthetic starting from ethane gas.

since that is very expensive. I found that second best for my application is Amsoil. It buys the base stock from Mobil so the benefits of a true Group 4 base stock is there. It is also almost just as stable above the 210*f mark. Since I run very high oil temps ~270* after cooler, filter, and 6' of lines. I need temperature stablity.

If you have more moderate oil temps, then this opens you to more options.