The C8 will have a 6.2L LT2 V8 engine
According to GM Authority, the C8 will be powered by GM's upcoming 6.2L V8 LT2 engine and produce somewhere between 480-500 horsepower and 480 lb-ft of torque. The LT2 will be a modified version of the LT1 and could come with upgrades to the Active Fuel Management system and valvetrain.
The engine will be partnered with a 7-speed dual-clutch transmission. GM Authority says "A grand total of zero sources have so far told GM Authority that a manual transmission option will be available."
he 6.2L LT2 V8 is nearly identical to the 6.2L LT1 V8, which can be found in the current Corvette C7 Stingray and Grand Sport, as well as the Chevrolet Camaro SS and new Camaro LT1. However, the LT2 receives a few minor modifications that enable fitment in the mid-engine configuration of the Corvette C8. What’s more, the LT2 may also feature a few other improvements compared to the LT1.
GM Authority has heard of but has not been able to corroborate with a full degree of certainty updates to the Active Fuel Management system (enabled in the Eco driving mode) and valving improvements that diminish friction, delivering smoother and more efficient operation.
Other than that, the LT2 will have the same displacement of 6.2 liters (376 ci) as the LT1, along with the same OverHead Valve (OHV), or push-rod configuration. Supporting technologies will include Direct Injection, Variable Valve Timing, and Active Fuel Management.
Link: Mid-Engine Corvette C8 Engine Will Be 6.2L LT2 V8 | GM Authority