Mercedes-AMG is making a decisive return to V8 power, heralded by the incoming CLE 63 Mythos coupé.

AMG’s variant of the CLE has thus far been available with only a turbocharged straight six, but the Mythos will bring a new V8 derived from that introduced by the facelifted S-Class.

The twin-turbocharged 4.0-litre engine has a flat-plane crank – typically reserved for supercars – and in the S-Class it produces 530bhp and 553lb ft. That's sufficient to propel the two-tonne saloon from rest to 62mph in 4.4sec.

AMG is expected to turn up the wick on the powerplant for the new CLE 63 Mythos, which is the second car in its exclusive Mythos range, following the SL Purespeed roadster. That car cost £664,000 and just 250 examples were made.

It's possible that the CLE’s version of the V8 could tip over 600bhp, giving it a 0-62mph sprint time of less than 4.0sec.

The coupé’s chassis will undergo significant modification to cope with the extra power. A new prototype has been caught testing at the Nüburgring sitting notably lower and wider than the existing CLE 53. It also wears different bodywork to previous test mules, with a more cohesive, motorsport-inspired look lying beneath the camouflage.

Indeed, it bears a strong resemblance to AMG’s previous Black Series models, yet it appears even more extreme.

AMG’s return to V8s comes after its attempt to downsize engines and make up for the power deficit with hybridisation was panned.

An AMG insider previously told Autocar that the four-cylinder plug-in hybrid powertrain used in the C63 and GLC 63 “failed to resonate with our traditional customers”. 

What's more, the cost of re-engineering that four-cylinder engine (also used in the SL 43 and A45) to meet the incoming Euro 7 emissions standards was “very high”, said Autocar’s source, prompting the rethink.