May 1, 2006
Welcome to a whole new world in Mustang performance. Our latest project car is an '05 Mustang GT owned by Kenny Moss, the former world-record holder in Street Outlaw. The only option on this car is an automatic transmission, and during the next few months we're going to show you just how wild one of these new Mustangs can be. Ken gave us the keys and told us to have a good time. Thanks, Kenny!

Longtime readers of 5.0 Mustang & Super Fords magazine and fans of heads-up Mustang drag racing in general will be quite familiar with Kenny "The Stud Field Mouse" Moss and his series of hot Mustangs. Kenny and his Baby Blue LX hatchback first slammed onto the scene in 1998 when he shattered the Outlaw world record with a jaw-dropping 8.35-second e.t. on 28x10.5-inch tires. That came with a wild ASSC Vortech-supercharged combination and a stock TRZ Racecars suspension. The legend of Baby Blue was followed by a Sonic Blue '03 Cobra that graced our cover on the July '04 issue as a ProCharger test mule. Since then, Kenny, like the rest of the free world, has become entranced by the possibilities presented by the newest Mustang. Retro styling; a solid, fresh chassis; and a raging 4.6 Three-Valve Modular V-8 that just begs to be modified-the new Mustang has something for everyone.

But months before Kenny took delivery of his car, there was a great deal of angst over which option boxes to check. It had to be blue (of course), and Ken told Ford it could keep the wing. He also checked the base interior option to save the weight, although the Pimp Red interior was inviting. But the one decision that really kept our boy Kenny up late at night was which transmission to go with. He called us for weeks, then right before good buddy Bruce Hemminger, new-car sales manager at Van Drunen Ford, placed the order, Ken decided to go with the five-speed automatic.

Our test car was purchased by Ken Moss (right) through New Car Manager and NMRA racer/crew chief Bruce Hemminger of Van Drunen Ford. Here's a shot of the proud new owner picking up our test car.

Intrigued by the possibilities of throwing around a brand-new Mustang with its equally fresh automatic transmission, we convinced Ken that he should just hand us the keys. (Hey, he got a couple of 5.0 Mustang & Super Fords magazine license plates out of the deal!) A tentative plan for modifications was laid out, and our friends at Paul's Automotive Engineering agreed to do all the modifications. Thus was born our newest project car: Automatic Weapon.

The obvious angle we'll be playing up with this car is answering all the questions regarding the new 5R55S five-speed automatic transmission. How much power can the transmission take? What modifications work with this transmission? What special tuning does the transmission require? Does the drive-by-wire programming really mess with the car? How much power will the stock Three-Valve take before eating itself?

The first stop was the rollers at Paul's Automotive Engineering, the Cincinnati Mustang superstore that will act as base camp for the car throughout its buildup. In stock trim the automatic-equipped GT belted out a respectable 242.9 rear-wheel horsepower and 257.6 rear-wheel torque with just 1,300 miles on the clock. Estimating driveline loss at 22 percent, that gives us 296.5 hp at the crank-right where we should be.

Hopefully, before Kenny gets his car back, we'll have poked and prodded every aspect of the transmission while building up one fast street car. Sure, we fully expect to have spilled tranny guts on the floor, but not before we put some serious beans to it. In the end, we're looking to have a lot of fun with this car, and that's what this hobby is all about.

As delivered, the automatic GT Mustang is an amazingly capable performance car. Forget everything you think you know about Ford's lazy transmission from AOD days gone by. This car is for real, and it will keep right up with and sometimes beat its five-speed manual brothers (depending on who's doing the driving). The car comes equipped with a 3.31:1 final drive gear, and the 5R55S transmission features a wonderfully low 3.22:1 First-gear ratio that immediately gets the action going.

As you can see by the accompanying chart, the 5R55S transmission has gear on top of gear, especially when compared with the First gear (2.84) of the venerable 4R70W automatic in the '04 Mustang V-8 it replaces. This is most noticeable in part-throttle applications around 20-40 mph. Stand on the gas, and this Mustang instantly moves out. In the old days, AOD owners had to endure a long wait for the right gear to be chosen, then an insufferably long period of time for acceleration between gears. With a tight gear ratio, four usable gears, and Overdrive, this is a fun car to drive.

GEAR 4R70W 5R55S
First 2.84 3.22
Second 1.55 2.29
Third 1.00 1.55
Fourth 0.70 1.00
Fifth n/a 0.71