Small cars and Cadillac haven't, historically, gone hand in hand. But they will in the near future, as General Motors is already stepping up work on its new 3-Series and C-Class rival.

The latest addition to the Cadillac lineup, dubbed the ATS, will slot in below the current CTS and should be on sale in time for the 2014 model year, but apart from those tentative details we don't know too much about the car.

We have reported in the past that there will likely be a flagship model complete with a next-generation small block V-8. GM’s new small block engine family will have improved fuel efficiency through direct injection as well as an advanced combustion system design. The engines will rely exclusively on aluminum blocks, which are lighter and contribute to their improved fuel efficiency. In addition to being E85 ethanol capable, these engines are being designed with the capability to meet increasingly stringent emissions standards expected throughout this decade.

Now we have a highly speculative ATS spec sheet by way of the Cheers & Gears forum to whet our appetites. Though we can’t confirm its authenticity, most of the details match what we already know.

2014 Cadillac ATS spec sheet

2014 Cadillac ATS spec sheet

First and foremost, the new Cadillac ATS-V is rumored to feature a 6.2-liter V-8 developing 470 horsepower and 428 pound-feet of torque.

That’s more than the Mercedes-Benz C63 AMG, the bad boy of the current crop of executive sports sedans.

According to the spec sheet, new features of the ATS-V’s engine will include full aluminum construction, direct injection, variable valve timing and cylinder deactivation technology.

Transmissions are likely to include either a six-speed manual or six-speed automatic, the latter seeing the new sports sedan return a possible 16/25 mpg city/highway fuel economy.

Other models in the ATS family should include a mid-level V-6, which will likely sport the same 3.6-liter V-6 from the CTS and output 330 horsepower and 280 pound-feet of torque.

Rounding out the ATS family is thought to be an entry-level four-cylinder model powered a 2.0-liter turbocharged mill with 270 horsepower and 250 pound-feet of torque on tap. Understandably, it should be the most fuel efficient of the bunch with an expected fuel economy of 22/32 mpg city/highway. Interestingly, this particular model is expected to sport a new eight-speed automatic transmission.

We'll keep you updated on any news as it breaks. In the meantime, check our previous story for details about coupe and convertible variants of the new 2014 Cadillac ATS.

_______________________________________

Follow Motor Authority on Facebook, Twitter, and Google+.