Sometimes Horsepower Just Isn't Enough

Stuffing an immensely powerful engine into a conventional vehicle — an affliction Ward's has dubbed Too Much Engine disease in the past — is not necessarily a recipe for greatness in the eyes of 10 Best Engines judges.

Enter the trio of Ford Mustangs that recently galloped into our office for our annual evaluation: the workhorse GT, the thoroughbred Shelby GT and the imposing Shelby GT500, which is more of an untamed bucking bronco with its 500 hp of iron-block mayhem balancing precariously atop its front axle.

When compiling the nominations earlier in the year, some figured the GT500 as the odds-on favorite to win in '07, with its 500-hp supercharged V-8 far and away the most powerful engine ever tested by Ward's for the competition.

But it was not meant to be, as this year's panel was swayed more by the balance and smoothness of the lesser steeds than by the outright authority of the bigger V-8.

To be fair, the limited-edition GT500 is a great car, and its Ford GT-derived 5.4L DOHC mill is equally praiseworthy, especially considering the whole package, complete with authentic Shelby heritage and an all-American V-8 soundtrack, can be had for less than $45,000.

Despite the GT500's ability to warm the globe with giant clouds of tire smoke, it was the volume Mustang GT and stepped-up Shelby GT, with their proven, twice-named 10 Best Engines-winning 4.6L SOHC V-8s, that won over the panel.

For '07, the Mustang GT's standard 300-hp mill is uncorked for the Shelby GT through the use of a free-flowing cold-air intake and exhaust from Ford Racing. Result: 325 hp.

Coupled with shorter rear-end gearing for improved acceleration; a nearly 500-lb. (227-kg) weight advantage over the GT500; and a more equal front/rear weight distribution; the Shelby GT invokes ear-to-ear grins every time the accelerator pedal comes into contact with the floor.

In contrast, the GT500 feels too heavy in front during cornering and only feels ready for unleashing on the straightaway.

True, the Shelby GT lacks its big brother's thundering propulsion but more than makes up for it with a bellowing exhaust note, more focused chassis and powertrain and the comfort of feeling less like one of ExxonMobil Corp.'s indentured servants when stepping on the throttle.

In addition, the 93-hp/L specific output of the low-volume GT500's mill is nearly on par with several high-output, normally aspirated V-6s and well below that of most high-output turbo 4-cyl. engines. There definitely is room for improvement.

All this adds up to packaging. The Shelby GT — and the Mustang GT to a lesser extent — excels with its combination of affordability (mid-$30,000s), attitude and practicality.

In the end, the GT500 comes off as a brute that makes no excuses for its shortcomings.

But when was the last time a bronco won the Kentucky Derby?