here is the second part. On edmunds.com they have a nice video to go along with it:

http://www.edmunds.com/insideline/do...hotopanel..1.*


The admiral of the aftermarket meets the Prince of Pony Cars
By Josh Jacquot , Senior Road Test Editor

Date posted: 02-01-2007


"I'll tell you one thing, there's nothing like building up an old automobile from scratch and wiping out one of these Detroit machines. That'll give you a set of emotions that'll stay with you. Know what I mean?"

Maybe we've watched Two-Lane Blacktop a few too many times, but we couldn't agree more with the maniacal and sleep-deprived character G.T.O. And to prove it, we've spent months modifying our long-term 2005 Mustang GT in an attempt to outperform Ford's 2007 Shelby GT500.

With 500 horsepower, the Shelby GT500 may be the king of all Mustangs, but the king don't come cheap. In fact, it's honkin' expensive. With a list price of $41,675 it costs nearly $20,000 more than we paid for our long-term 2005 Mustang GT. Not to mention that bringing home a GT500 today will set you back more like $75,000. Which got us thinking....

Why not build our own? So we did. Last week, in the article titled "Project Mustang GT vs. Shelby GT500, Part 1," we detailed the modifications we made to our Mustang GT. Modifications that totaled $13,063, which is more than we planned on spending, but still less than a new GT500, even when our Mustang's original sticker price is factored in.

Was it money well spent? Let's find out.

The contest

Our showdown between the 2007 Shelby GT500 and our own supercharged 2005 Ford Mustang GT became a weeklong three-stage contest of performance and endurance.

First we went to MD Automotive in Westminster, California, and ran both cars on its Dynojet chassis dyno to compare engine power. Then we headed to our usual test facility and ran them through our standard instrumented tests to compare handling, acceleration and braking.

Finally we got serious and headed for the Radical Loop at Spring Mountain Motorsports Ranch in Pahrump, Nevada. The Radical Loop is a 10-turn, 1.5-mile road-racing circuit with tight corners and relatively modest straightway speeds, so it's appropriate for evaluating street cars.

Spinning the rollers

On the dyno, the GT500 first put down 432 hp and 418 pound-feet of torque. After we discovered (following much wrangling with Ford) that our test car had been equipped with a faulty air filter, we returned to the dyno for a second test and the GT500 put down a healthy 448 hp and 420 lb-ft torque. Read our full test of the GT500 for all the details.

When we lashed the project Mustang to the dyno, it put down wildly erratic numbers because of rough combustion at high rpm, so peak power varied by as much as 30 hp. Something wasn't right, and we were puzzled because the problem wasn't obvious while driving the car on the street. We measured the air/fuel ratio — a telltale indicator of lean, potentially catastrophic tuning — and found it to be between 12.9:1 and 12.2:1 throughout the heart of the power band. Ideally, an air/fuel ratio in the range of 11.0:1 would be rich enough to eliminate lean surge, plus it would improve the engine's long-term durability by forestalling detonation.

It's possible that we weren't getting enough spark at this relatively extreme level of supercharger boost, since the project Mustang's spark plugs had been in place for 20,000 miles. It's also possible that Vortech's engine management system isn't tuned perfectly. Whatever the case, the most representative dyno run with our supercharged engine produced 376 hp and 353 lb-ft of torque. This is a 42-percent increase in horsepower from the stock engine's 265 hp, and a 28-percent increase in torque from the V8's initial 276 lb-ft. Even so, our car was a good bit off the GT500's power numbers.
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The str