Do you need a work permit? desogen Will it be as good down the quarter mile? We're guessing the upgraded 5.0-liter V8 should more than make up for any loss in traction caused by disconnecting the rear wheels. Motor upgrades there are largely predictable, including some borrowed from the current Boss 302. It's the 2.3 liter EcoBoost motor that will really help the new Mustang compete globally. Today's V8 makes 15 MPG in the city. The new one should do slightly better, but that still won't fly in a place like Norway, where gas prices exceed $10 per gallon.