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American Muscle’s Story on Building a 400 RWHP V6 Mustang

American Muscle has completed their V6 Mustang build up and the results are staggering – four hundred horsepower to the the rear wheels and 12s at the drag strip. After passing through three previous stages of modifications, the car is, in their words, “completely transformed from a moderately responsive and  dumbed-down V6 slushbox into a hard and fast-shifting beast.”

Along the way, this car picked up some attitude in the looks department as well. OK, we’re getting ahead  of ourselves here, so let’s start from the beginning of a build that was done right and may open your eyes to just what 3.7-liters of Pony Power can do when properly motivated.

Stage 1: The Awakening

Before anything was done to the car, they needed to establish a performance baseline against which all future changes could be judged. So, the first step was to strap the dead stock V6 automatic Mustang onto a chassis dyno. The results came back at 260 RWHP and 241 RWTQ. The next step was to take the Mustang to the local 1320 and log some results. From that, they came back with a best run of 14.135 seconds @ 100.85 mph.

With that done, the mods could begin. Stage 1 wasn’t overly ambitious, but represented a good approach to finding the easy gains. After installing an Airaid cold air kit and a Bama Performance 93-octane custom tune, it was time to hit the dyno once more. With just these two changes in place, the car punched out 22 additional RWHP and 30 more ft-lb of RWTQ. At the track, these changes trimmed the ET to 13.647 and boosted the trap speed to 103.89 mph.

Cosmetic adjustments for this stage included a set of pre-painted side scoops, pre-painted Eleanor-styled louvers, pre-painted mirror covers and a magnetic rear decklid blackout panel.

Stage 2: The Gathering

Checking out the time slip from the previous track run, there was some time being left on the table at the 60-foot mark. The factory stock 2.73 rear axle gears were certainly part of this, along with the 17-inch all season tires. Before any mods were started, the Mustang was hitting a short time of 2.219 seconds.

So, for this Stage the plan called for installing a set of Ford Racing 3.73 rear gears, along with an Eaton 31-spline limited slip differential. Updated wheels and a set of Nitto drag radials for the rear end would certainly help out in the traction department. Going with a staggered fitment, they installed  machined 2010-style GT500 18-inch wheels, 9-inches wide in front and 10-inches wide in the rear. The new tires are Nitto Extreme Performance NT555, sized 255/45-18 in front and 275/40-18 out back.

The proof was in the timeslip, tough, as a return trip to the local strip confirmed expectations. With the Stage 1 and 2 modifications complete, they had shaved more than .15 seconds off the 60-foot time, with a best of 2.060 seconds. A set of Borla Atak axle back mufflers were also installed, along with some striping to add a little visual distinction.

Stage 3: The Handling

Changing focus now to street performance, the American Muscle folks completed a few exterior modifications before heading out to New Jersey Motorsports Park for some track time. These guys have tough jobs, don’t they? They used three different measures to baseline the car again.

These were 0-60 mph time, time through a slalom course they had set up and time to complete a lap of the road course from a standing start. After some initial runs, they pulled the car into a garage on site and installed  a Ford Racing Handling Pack along with a one-piece aluminum driveshaft. With that complete, it was time to heat up the tires again.

These upgrades managed to shave 0.7 seconds from the 0-60 time, which reportedly tumbled from 5.0 to 4.3 seconds. The slalom performance was similarly hit, dropping from 9.7 seconds to 8.1 seconds. Finally, a lap around the road course showed a 1.1 second improvement. When you think of that time in terms of car lengths, the number is a lot bigger than it sounds. This Mustang has come a long way from its original condition and performance. Sporting demonstrated improvement on street and strip, as well as looking good, it’s time to take this Mustang to the next level.

Stage 4: The Insanity

The exterior changes this time add as much ‘Bad Boy’ attitude as does the Procharger Tuner Kit. The Raxiom headlights and Saleen blackout grille work well together in creating a unique look for what has become a very unique pony car.

Matching the Procharger kit up with a set of 80# fuel injectors, the American Muscle took a conservative approach this time around. Dialing in just six pounds of boost, they updated the Bama Tunes programming for the supercharger. BBK full length headers and an an off-road X-pipe were also installed.

A trip back to the dyno pushed 400 RWHP and 340 RWTQ into the rollers, for gains of 156 HP and 141 ft-lb. A return trip to the track was rewarded with a timeslip showing 12.47 @ 113.5 mph. In their closing comments on this Stage, the American Muscle guys noted that, “On a cooler day, I have faith this thing would have gone low-12’s @ 115 mph or so. Hard to argue with those times, and especially at only 6 psi.”

For those of us that called for a return of the Mustang LX, it is here and its name is V6. There’s no longer any need to pretend to be something else, and those that continue to dismiss the V6 out of hand, do so because they haven’t come up against one yet… and certainly not against one like this.