Khodrocar - Several trademark filings suggest that Mercedes-Benz might be considering revised model names for denoting its latest powertrains. Registrations like this always tricky to take seriously because a company can reserve a name and never use it. However, these titles fit with recent rumors about the automaker's future.
Rumors indicate that the 73 moniker will be for a version of Mercedes-AMG's 4.0-liter biturbo V8 with the addition of plug-in hybrid parts that would give the vehicles in excess of 800 horsepower (597 kilowatts) and 738 pound-feet (1,000 Newton-meters) of torque.
Meanwhile the 63 title would reportedly be for an upgraded version of the 4.0-liter biturbo V8 developing 612 hp (456 kW).
The 53 models here present quite a mystery. The CLA, GLA, and future GLB-Class ride on Mercedes' front-wheel-drive-based platform. However, the existing vehicles with this name, e.g. the CLS53, E53 coupe, and E53 convertible, use a transversely mounted 3.0-liter turbocharged straight-six engine with a 48-volt electrical system and small electric motor for a hybrid boost. It's unlikely this setup would fit the FWD models because they use a transverse powertrain layout. Perhaps, Mercedes has a hybrid drivetrain on the way for them.
The 40 and 50 models are a bigger mystery. The recently unveiled A-Class comes as the A 200, A 250, and A 180d, which indicates that Mercedes doesn't plan to use two-digit monikers on the hatchback, despite it having new engines.