There's overwhelming evidence to suggest this mill will also power the C8 'Vette.

We just learned yesterday about Cadillac’s amped-up CT6 sedan in V-Sport guise, packing an impressive 550 horsepower (410 kilowatts) from an all-new 4.2-liter biturbo V8. That should make for a very lively motivator in Cadillac’s flagship, but when we read the press release there was a sense of déjà vu. The engine is all-new, but we could swear we’d heard something about a 4.2-liter V8 before.

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We have – in rumors about the much-anticipated mid-engine Chevrolet Corvette. Back in November we were tipped off to a document from IHS Markit that referenced both the Corvette and a 4.2-liter V8, among other engines. Specifically, it pointed to 4.2-liter V8 production in limited quantities beginning in 2019 for a car that should be the mid-engine ‘Vette. And now, we have a confirmed 4.2-liter mill in the General Motors stable. Interesting.

Cadillac CT6 V-Sport
Cadillac CT6 V-Sport

We aren’t the only ones to pick up on this connection. The folks at Corvette Forum not only have a blog post about it, there’s a thread dedicated to talking about the new mill and honestly, there’s all kinds of evidence to suggest this engine will see duty in the next Corvette. For starters, its “hot V” design with the exhaust manifolds running between the cylinders and turbos at the top of the engine makes for a very compact design, despite its big dual overhead cam heads. Furthermore, the engine will be built at GM’s Performance Build Center in Bowling Green, Kentucky – the same place where Chevrolet builds the Corvette. Very interesting indeed.

A couple things don't quite match up, however. Estimates last year suggested a boosted 4.2-liter V8 would make upwards of 650 hp (485 kW) for the ‘Vette. Cadillac’s new engine is well short of that obviously, and with the turbos already making 20 pounds of boost there may not be much room to add more. Also, the above photos claim to show CAD renders of the mid-engine layout, and clearly there are manifolds on the outside of the engine.

There's still room to connect the dots though, because those earlier engine rumors also include a larger 5.5-liter V8 that could make over 800 hp (596 kW). The 4.2-liter could be a base engine, and it's not like 550 hp in a small mid-engine sports car would be slow by any means. The renders then could depict the bigger engine providing the knockout punch.

In any case, it’s extremely likely that Cadillac is giving us the first look at the C8 Corvette’s new engine. One of them, at least.

Source:  Corvette Forum, 2

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