The new 3.7-liter V6 is a dual-overhead cam engine that makes 305 horsepower at 6500 rpm and 280 pound-feet of torque at 4250 rpm.   Those numbers are close to those of the outgoing V8.   Fuel economy is also better, thanks in part to new six-speed manual and six-speed automatic transmissions for 2011 to replace the previous five-speeds.  

Fuel economy is an EPA-estimated 19 mpg city and 31 highway with the automatic and 19/29 mpg with the manual (versus 16/24 mpg and 18/26 mpg for the 2010 V6).  

Ford wouldn't provide 0-60 acceleration times for either engine, but we suspect the V6 can get there in less than 6.0 seconds, which is about a second quicker than the old engine.   The new engine sounds great, too, emitting a muscular American growl.   Both new transmissions work well with the engine.   An autocross course revealed that the automatic's gears are spaced a little tighter than those in the Chevy Camaro.   The result was more willing response in lower gears at low speeds.   Basically, it means that power is there when you want it.   The manual works well, too, but the shifter doesn't have quite the satisfyingly positive action that enthusiast drivers might like.   We also found the clutch is a bit hard to modulate in first and second gears, making for some jerky starts.  

The Mustang GT is even better.   The 5.0 designation is important in Mustang history.   The 1969-'70 Boss 302 displaced 5 liters, and in the 1980s, Ford resurrected pony car muscle with a 5.0-liter V8.   That engine later gave way to the 4.6 V8 that was used until last year.   For 2011, Ford introduces an all-new dual-overhead cam 5.0-liter V8 that puts all of its predecessors to shame.   Not only does this engine have 97 more horsepower and 65 more pound-feet of torque than the outgoing 4.6, but it also weighs about 100 pounds less to improve handling, and gets better fuel mileage.  

The 5.0 transforms the Mustang into a muscular pony car with power to spare.   It will easily smoke the tires with the manual or automatic transmission and it provides a big kick in the pants when floored from a stop.   Passing is just a matter of a twitch of your throttle foot, and the whole experience is backed by a glorious rumbling soundtrack that is distinctly American.  

With the new V8, Ford has caught and possibly surpassed the usable power of the Chevrolet Camaro SS.   While previous Mustangs just couldn't keep up with GM's 427-horsepower 6.2-liter V8, the 5.0 makes the new Mustang just as fast or quicker from 0 to 60 mph and in a quarter mile.   At the press introduction, Ford provided Mustang GTs and Camaro SSs with automatic transmissions to drive in a 1/8-mile drag race.   The Mustang was consistently about a half-second faster than the Camaro.  

Over the past two years, the Mustang chassis has been upgraded and stiffened, which means it rides tauter, turns in quicker and has less pitch, dive and body roll than any previous Mustang.   A front Z brace was added for 2011, helping to increase torsional rigidity by 15 percent.  

Antilock brakes, traction control and AdvanceTrac yaw control are standard on all models.   For track work, both the traction control and the yaw control can be turned off (but not the ABS), and there is a Sport mode which allows higher handling limits before traction and yaw controls are called in to save the day.  

The Mustang GT is an absolute blast to drive.   The car has a fairly light, tossable feel and it responds quickly to driver inputs.   It is very willing to attack turns, with the new electronic power steering providing a light but natural feel.   The car is extremely quick to transition from left to right and back again with a minimum of body roll, dive or pitch in the suspension.   The brakes are larger for 2011, and the Brembo brake package adds larger brakes that should be the choice for anyone who wants to take their car to the track or drive regularly on twisty mountain roads.   And the sound and power of the V8 is fantastic.  

Formerly a glorified rental car, the V6 model is now nearly as much fun to drive as the GT.   A new Performance Package for the 2011 Mustang V6 includes the GT suspension and an additional strut brace.  

The convertible benefits from more structural rigidity for 2011.   The changes include a tower-to-tower front strut brace, a stiffened V-brace, the addition of the aforementioned front Z-brace, added A-pillar stiffening foam, and a stronger secondary crossmember.   These changes make the ragtop much more solid than in the past and even stiffer than competitors from Infiniti and Lexus.   That translates to competent handling, though the stiffer coupe remains the choice for the ultimate in handling and chassis rigidity.  

In short, the Mustang is the best it's ever been and is the model for pony car sportiness and power.   The only drawback remains the solid rear axle, which can cause a busy ride on bumpy roads because jolts to the rear axle are transmitted from side to side.   An independent rear suspension would deal with bumps much better as it would isolate road imperfections.   That's a small price to pay considering how much better the rest of the car is.