Ford’s iconic Mustang is only due for an update next year but it appears developers will be completely revising the powertrain lineup in addition to tweaking the car’s sheet metal. Fears of impending CAFE regulations has got Ford management worried, so much so that officials are considering speeding up the introduction of more fuel-efficient engines, namely the new twin turbo EcoBoost V6.

The V8 lineup is also tipped to receive an overhaul. MotorTrend is reporting that 2010 Mustangs could be available with a new 5.0L SOHC V8 in replacement of the previous 4.6L unit. This new 5.0L unit could also eventually spawn a modern version of the original Boss 302 in a limited edition Mustang GT with power up around the 350hp level. A smaller 4.6L V8 should also be available. This will be the same unit as found in the current Bullitt-edition cars. Developed using parts from Ford Racing Technology, the Bullitt version features a 315hp 4.6L V8 engine with 440Nm (325lb-ft) of torque.

The 4.0L V6 will still be available in base versions. If offered, the EcoBoost V6 model will cost similar to the V8 versions and will output similar power and torque figures. Ford claims the new EcoBoost six-cylinder can churn out up to 415hp and has the same torque levels of a big-cube V8.

As for the high-performance Shelby models, the source claims the GT500 will continue in the 2010 model year and it will retain its 500hp 5.4L supercharged V8. Ford, meanwhile, has also been testing supercharged versions of its own 5.0L V8 and is rumored to be developing its own flagship to compete with cars like the new Corvette ZR1 and Viper SRT10.