The Camaro Z/28 will be returning for an encore act and it might be using the next-generation of Chevrolet's small-block V8.
Car and Driver reports that GM is working on the next-generation LT engines, codenamed LT6 and LT7. These new V8 engines will lose the pushrods and two-valve combustion chambers that have been a key part of the small-block V8. Instead, the new engines will feature dual overhead camshafts, four-valve combustion chambers, flat crankshaft, titanium connecting rods, and possibly dual injection (port and direct). For the Z/28, a 5.5L LT6 could produce 700 horsepower (that's without any sort of forced induction).
Car and Driver speculates there could also be a twin-turbo LT7 that could be used in the next Corvette, high-performance Camaros, and Cadillacs.
The Camaro Z/28 could arrive next year as a 2019 model year vehicle.
Source: Car and Driver