As impressive as the base mid-engine is, rumors are swirling that the upcoming C8.R racecar and inevitable will be powered by a monstrous twin-turbo flat-plane-crank V8.

We already heard reports over the weekend that the upcoming Z06 would get a twin-turbo engine making around 800 horsepower and potentially more than 700 lb-ft of torque, which is ridiculous. But to get all that power and torque, GM will use a flat-plane-crank engine.

From Motor Trend:

You’ve heard the rumors and you’ve seen the leaked CAD drawings. The car world has been speculating about overhead cams and turbochargers and flat-plane cranks in the backs of for months now, but we’ve confirmed with a deep source on the Corvette team that the upcoming and, more crucially, the will be powered by a flat-plane-crank twin-turbo dual-overhead-cam V-8.

“Everyone thinks it will be a small block, but it won’t be,” said our source. “Listen to the race car.”

Here’s the video of the race car which Motor Trend cites as audible evidence of the supposed flat-plane-crank V8:

Key characteristics to listen for: a higher-pitched exhaust note, a consistent exhaust note without the pushrod’s staccato bass line, higher RPM than a pushrod motor typically reaches characterized by longer times between upshifts, and lightning quick downshifts wherein the engine spins up to higher RPM much faster than a pushrod engine.

I’m extremely skeptical of using video of a prototype as solid evidence of what’s going on under the hood on a future production model, but Motor Trend seems fairly convinced, and the move to a flat-plane-crank engine design would certainly help squeeze out some performance for the hot version of the Corvette.

All we know for certain, though, is that it will not be getting the new Cadillac-exclusive Blackwing V8, so Chevy is going to have to come up with something else.

As we pointed out over the weekend, the outgoing Z06 was far under the claimed 800 horsepower figure of the new one, making 650 hp and running into a ton of problematic cooling issues under consistently aggressive driving. Here’s hoping Chevy has unlocked a few secrets to sure the new one can hit more power and be sustainable.