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Heavy Metal Affliction 2004 Ford Mustang GT

John Schommer
Thursday, November 15, 2012


When you know what you like, why change? Sticking with what you know can result in a lot of happiness. You could say that doing so isn’t very adventurous, but that wouldn’t be right. To each their own, follow your own path — it will lead you to your destiny.


This week we meet Forza Community member John Abernathy of Irving, Texas—Gamertag JMARR8. Abernathy has owned three late model Mustangs so he definitely knows what he likes. He also can’t settle for the considerable power the venerable Ford small block puts out. In fact, that torquey power was like a lure for him that hit he bit hard with his second Mustang, and the hook was set. But let’s take a step back.


Abernathy is 26 years old, was born and raised in Irving, Texas, married his high school sweetheart and now has two little boys. Again, proof that Abernathy knows what he likes and doesn’t need to go about sampling the entire buffet before settling on his entrée. After graduating high school he drove a Mustang GT with a 5-speed, then took a job with the railroad as a conductor. He began saving and as soon as he could afford it traded up to a 2004 Mustang Cobra. Then he dug in and converted that potent bone stock Cobra into a twin-screw monster with over 600 horsepower. Suddenly the conservative image of this gentleman conductor who married his high school sweetheart and started a sweet little family changes to include a dire need for horsepower to feed his love of cars.



Raised by his mother with a younger brother as a companion, Abernathy has always loved cars. “Ever since I can remember, I’ve been a car nut, back to when I was about 4 or 5 years old, I would make car exhaust noises as my mom drove down the road.” When he earned $10 a pop for mowing his grandma’s yard he headed straight to the store and bought all the Hot Wheels he could. After a year of mowing he had about 100 cars, and by the time he was done collecting he had more than 400. He still has them too.


After getting married, when Abernathy wasn’t hanging out with his wife or in the garage installing upgrades, he was playing Forza, starting with Forza Motorsport 2. His wife has always been supportive of his need to modify, and so has his mother, even loaning Abernathy her car when his was sitting in pieces.


It’s clear that Abernathy has also balanced his love of Mustang’s horsepower and customization with being a good husband and reaching goals for his family. After he had built up the 2004 Cobra and gotten it just where he wanted it, he sold it to buy a house for his family. Then he started over and soon purchased the car we get to learn about today: a 2004 Mustang GT 40th anniversary edition. When purchased it was bone stock, but it didn’t stay that way for long.


“If you know me, I love the idea of a basically stock looking clean car on the outside with the stuff under the hood nobody expected. A total sleeper that would wake up the neighbors and never even think it would be the stock looking silver Mustang next door. I didn’t waste any time installing parts on the car and I did most of it myself.” That pretty much sums up Abernathy’s approach. His first modifications were simply cosmetic, blacked out headlights, taillights and side markers a chin spoiler and some other details.


Sometimes bad luck can turn in your favor. A couple months after finding out the cost of custom painting the rear deck between the taillights was too costly, Abernathy was rear-ended and in the process of the repair he was able to get this done at nearly no cost. A nice touch, and while nobody wants to have their car damaged, in this case it worked to his advantage.



Where’s the exhaust you ask? Abernathy has it dumping out just before the rear axle, “trying to make it look less like a GT, probably just the opposite anyone else would do, but I like being different.” Under the hood he initially went for a P-51 intake, larger throttle body, and injectors to feed enough fuel to serve the P-1SC Procharger pushing 8lbs of boost. He had to cut the hood under the GT’s cosmetic hood scoops to accommodate the intake, then ingeniously drilled out the fake venting holes in the hood scoops to let in air flow, resolving the significant heat produced by the supercharger. Now the Mustang made 402 rwhp and ran the eighth mile in 7.56 at 93mph and did the quarter mile in 11.92 at 111mph. Yes, this car is built for drag racing. But that wasn’t enough.


Abernathy changed out the heavy P-51 intake for an Edelbrock manifold and custom made race intake. The intake was so big that it required a larger throttle body so it was swapped for a 105mm one from Accufab. This is where Abernathy handed off the tuning to HPP Racing of Lewisville, Texas. Here Abernathy emptied his build budget resolving fuel system issues, eventually going with a return style fuel system and a larger 10lb pulley. HPP also added a Ram HD clutch to ensure reliability to serve all this new power.


The engine internals are now pretty much maxed out and on the dyno it hit 424 rwhp with a relatively moderate tune running on 93 octane pump gas. Although Abernathy did not get back to the strip before selling the Mustang to afford a second little boy in the family, he did thwomp his father-in-law’s C6 Corvette several times, and that made it all worthwhile.



Enjoy these photos of the car.


With the P51 Intake

With the Edelbrock intake

Ouch, high performance shops aren’t cheap, but they do good work.


If you have a car that you are passionate about and would like to share your story tell us about it in the request for community rides thread.


If you would like to compliment JMARR8 on his Mustang and horsepower affliction do so in the HMA thread.