2014 Mercedes-Benz S63 AMG

Despite being a relatively new engine in the grand scheme of things, the curtain may soon close on the twin-turbocharged 5.5-liter V8 found under the hood of many Mercedes-Benz AMG cars. Speaking to Australia's CarSales.com, AMG chief Tobias Moers said that the engine, as fitted in the 2014 S63 AMG (pictured), is at its maximum state of tune, and that more power cannot be eked out without threatening reliability. This engine produces a massive 577 horsepower and 664 pound-feet of torque in the new S63.

The forthcoming S-Class coupe and convertible models are expected to get this same AMG treatment, though Moers did not confirm this, along with updated versions of the E63 and CLS63 AMG. But beyond this, the M157 twin-turbo V8 is not expected to appear in any new Mercedes products.

So, what's next? CarSales.com states that the AMG version of the next C-Class will use an all-new 4.0-liter V8 that will, essentially, be created by bonding two of the 2.0-liter turbo engines from the A45 AMG (or CLA45 AMG) together. This 4.0-liter mill is expected to power the new, sub-SLS sports car, dubbed SLC.

Beyond that, a hybridized version of the 4.0-liter V8 could arrive, since Mercedes-Benz has made it clear that electrification will play a key role in the future of AMG. As Moers told CarSales.com, "It's clear depending on the segment – large SUVs, S-Class, whatever – in the future they will be assisted by electric motors... but there is no decision done, it is a discussion that must be done."