Our spies have captured footage with a Mercedes-AMG GLC 63 test mule dressed up like a GLC 43.

It was only a month ago when Mercedes-AMG introduced the GLC 43 which will temporarily serve as the range-topping version of the compact crossover. The prototype you see here looks virtually the same as the GLC 43, but under the hood it swaps the biturbo 3.0-liter V6 engine for a larger 4.0-liter V8, also with a biturbo setup.

You’d think the engine is sourced from the C63, but that’s not the case. That is because at the end of last month we learned from Mercedes-AMG boss, Tobias Moers, the crown jewel of the GLC 63 will actually use the E63’s hardware. That’s certainly good news if we take into account the forthcoming 2017 E63 S will have an insane 612 horsepower (450 kilowatts) and 626 pound-feet (847 newton meters) of torque. Maybe the beefiest model of the GLC range won’t be as potent, but rest assured it will have well over the 510 hp (375 kW) of the C63 S.

Also sourced from the new E63 AMG will be the nine-speed automatic transmission linked to an all-wheel-drive 4MATIC system developed from the ground up by Mercedes-AMG. Moers has promised the AWD layout has been engineered in such a way as to allow drift and provide that rear-wheel-drive feel.

It’s too soon to talk about performances, but obviously it will be way faster than the GLC 43 which hits 60 mph (96 kph) in 4.8 seconds and tops out at an electronically-limited 155 mph (250 kph). With the E63 S believed to cover the sprint in just three and a half seconds, the GLC 63 S is going to be an absolute rocket.

Look for an official launch of the GLC 63 at the beginning of 2017, with the GLC 63 Coupe to follow shortly.

Gallery: Mercedes-AMG tests V8-powered GLC 43 prototype to prepare GLC 63