Despite its displacement the 4.0L unit only generates 210hp (156kW) and isn't as gentle to the fuel bill as it could be. The Duratec 3.7L unit expected to replace it, however, will benefit from newer engineering and possibly also direct injection in the near future.
The engine won't slot into the Mustang until the 2011 model year, according to TheMustangNews, leaving the better part of a year for further developments. Most enthusiasts were let down by the current 2010 Mustang's (pictured) lack of powertrain updates.
There are a few handy comparisons in the Ford lineup, including the same basic 3.7L V6 as used in the 2010 Lincoln MKS. That unit is rated at a stout 273hp (204kW), and direct injection could bump that figure even higher. Add in another 0.2L of displacement, and 300hp (224kW) or more is within reach.
Other rumors afoot today have a 400hp 5.0L V8 sliding into the 2011 Mustang lineup as well, leaving ample room for a potent V6 underneath. This rumor is built around a comment made by Ford chairman Bill Ford, Jr. today on CNBC. Ford said simply, "we can give you the Mustang with 400 horsepower" in the context of contrasting the car against the upcoming electric Focus, and highlighting Ford's wide range of options. Innocent slip of the tongue or preview into the next-gen Mustang? You be the judge.
But of course, the cat-and-mouse game of rumor and official announcement still has to play out until early 2010 at least.