From the 2017 Manual:
For the 6.2L engine, premium
unleaded gasoline meeting ASTM
specification D4814 with a posted
octane rating of 93 is highly
recommended for best performance
and fuel economy. Unleaded
gasoline with an octane rated as low
as 87 can be used. Using unleaded
gasoline rated below 93 octane,
however, will lead to reduced
acceleration and fuel economy.
If knocking occurs, use a gasoline
rated at 93 octane as soon as
possible, otherwise, the engine
could be damaged. If heavy
knocking is heard when using
gasoline with a 93 octane rating, the
engine needs service.