My understanding is that dexos, dexos1, and dexos2 are standards or specifications that oils must meet in order to be approved for use in GM vehicles. Mobile 1 5-30 meets those specifications and is an approved product.
See attached list for approved oils. List may have been update since this link was published -
http://www.imakenews.com/lubritec/e_...454163.cfm?0,w
I had my 500mile change on my 2016 Z06 yesterday, 8/24, and went into the shop and watched. The dealer used Mobile 1 and said that IS the factory oil.
I also found the following statements in some Corvette articles ----
The Chevrolet Corvette is a high performance machine, both on the street and on the track, a legacy of automotive engineering. Mobil 1 racing and performance oils also represent the best in automotive technical engineering. It’s no wonder these two superstars continue to solidify their partnership with a recent announcement that Mobil 1 would remain the oil of choice in new ‘Vettes. The oil and gas giant recently announced a new lubricants technology agreement with General Motors (GM) for the Chevrolet Corvette, which includes Mobil 1™ motor oil as the factory fill for the upcoming 2015 Corvette Z06 and the current 2014 Corvette Stingray with the Z51 Performance Package.
Chevrolet also named Mobil 1 5W-30, which meets or exceed the GM dexos1® specifications, as the recommended service fill for all Corvette models on the street, while 15W-50 is recommended for on-track and high-performance applications.