Car Feature: Silver Bullet GTO

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photos by: Joe Didario

This One-Owner GTO has Stuck with his Car through Thick and Thin

Two-thousand four was an interesting year for General Motors performance cars. Still coming off of the cancellation of the F-body twins, both Chevrolet and Pontiac struggled to capture the attention of displaced pony car buyers with vehicles like the overpriced and underpowered SSR, and the rebadged Toyota/Pontiac Vibe. It seemed all was lost, until Bob Lutz came on board and dropped the GTO bombshell.

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Once previously suggested that General Motors bring the Monaro to the States in a 2003 GM High-Tech Performance article by Johnny Hunkins, the Holden Monaro coupe was rebranded as the fabled Pontiac muscle car — complete with two doors, rear wheel drive and a 350 hp LS1 under the hood. The reaction from the motoring press and the target audience, was mixed.

The first thing that stuck out to many, was the similarities in styling to the similar in size Grand Prix of the era (well yeah, it’s a Pontiac!), and the lack of hood scoops. Functional, or otherwise. Your author didn’t mind, though, for what it’s worth. We can get more into the details on the who’s, why’s and what’s here, but let’s not detract from the GTO-inspired story here.

Instead, let’s focus on the here’s and now’s, and delve deep inside this particular 2004 example, owned by Joe Forsten. Hailing from North Point, Florida, Joe has been the sole owner of this GTO since it had originally left the dealership almost thirteen years ago. It has undergone a few, subtle cosmetic changes over time, including the addition of the 2005-06 GTO hood, but the real story lies beneath the bonnet (see what we did, there?) and Joe himself.

As Forten relays to us, he actually picked it up as a 20-year old young man, after he traded in his ’96 Mustang GT convertible in for it. Growing up with an old man who owned quite a few classic GTOs, Joe had always promised himself that he would one day own one himself. When Pontiac dropped the 2004 example, he was onboard! Unfortunately, it wasn’t without its downsides.

Ridiculed and mocked by “real GTO” owners and enthusiasts, like so many others, he persevered with his modern interpretation of what the GTO would have ineveitibly become, had it been allowed to stay in production, maintained its RWD/V8 layout and two-door body style in the first place. Haters hate, though, but that didn’t stop Joe from persevering. In fact, even with the 3.46 gears and T-56, he managed to click off a 13.29 in completely stock format — not bad!

It wasn’t long until the “mod bug” had bitten Joe, though, and it started in an unusual way — but maybe not to GTO enthusiasts; a Sport Appearance Package upgrade. After stumbling upon an image on LS1GTO.com, Joe was surprised to learn that it was indeed a GM option on production 2005 (and later, 2006) GTOs.

Wasting no time, Joe placed an order for the kit that would set him back three months and $3000. To Joe, it was worth it, and not only updated the look of the car but also added additional “attitude” that many felt the car lacked. As a surprise bonus, the kit also included low restriction mufflers.

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The low-restriction mufflers were twofold; they added some growl to the soundtrack and they also bumped the horsepower count up a notch. This ultimately led Joe to increase the horsepower count substantially, having selecting a head/cam combination that would really wake up the one-time sleeper Goat. Courtesy of the installation prowess at Tiberio Performance, and the tuning efforts of Jeremy Formato at Fasterproms in Tampa, Florida, the horsepower jumped up to 430 hp and 396 lb-ft of twist to the rear tires.  The quarter-mile drag time dropped considerably, from a 13.2, to consistent 11.3s and 11.4s on drag radials.

This made Joe happy — ecstatic, really. However, he eventually became very used to the revised performance level and he wanted even more — a Vortech blower lived with the LS1 for a brief moment, spiking the power up to 608 hp and 590 lb-ft to the tires. Coincidentally, the original 346 LS1 decided then and there that it no longer to join Joe on his power-hungry journey, and let go prematurely. The timing couldn’t ‘t be worse, as the economy had just crashed and despite the insistence of his friends telling him otherwise, Joe elected to keep the car and build a new engine as time and cash allowed.

However, he didn’t simply want to replace it with another factory-spec LS1, he wanted to go full-bore 383 stroker… with a dose of giggle gas! He was all-in now, and there was no retuning to stock at this point.

Starting with an Eagle billet crank and rods, and MAHLE forged pistons, Joe built his 383 from the ground up with solid hardware. He topped the short block off with a COMP Cams hydraulic bumpstick, speccing in at 232/234 duration, 595/598 lift and a 112 LSA. The heads are Livernois Motorsports CNC-ported Stage 3 castings — stuffed with OEM 17 rockers and Manley valves, that are paired-up with a F.A.S.T. 92mm intake manifold and PTM 92mm throttle body. A stock MAF sensor, K&N filter and OTR cold-air kit handle the rest of the induction side of things.

The spent fumes are expelled through a set of budget-friendly Pace Setter 1-3/4 inch long-tube headers and X-pipe, QTP cutouts and Magnaflow 2.5-inch diameter exhaust. The sound is incredible, and the components all working together guarantee excellent flow characteristics. balancing out the air/fuel ratio is a Lingenfelter pump, 52-lb/hr injectors and a stock regulator.

With a 150-shot Nitrous Outlet wet kit onboard, the power level jumped up to a rock-solid 515 hp and 543 lb-ft of torque to the rear tires. This ultimately resulted in a 10.75 at 129 mph with a relatively stock suspension setup. In fact, the only chassis or suspension mods that Joe noted in his tech sheet is a BMR driveshaft loop, cradle bushings, axles and drag bags, Pedders rear drag springs, KYB shocks in the front, Koni adjustables in the rear and nothing else.

It still maintains its OEM sway bars, and upper and lower control arms all the way ar0und! However, DBA slotted rotors sit inside the calipers, and Joe had the factory ’05-06 18-inch GTO wheels powder coated black, and wrapped in Nitto NT555 rubber all the way around. They measure in at 235/40 in the front and 275/35 out back.

Incredibly, the manually-shifted T-56 still sits in place, with a Monster Stage 3 clutch and chromoly flywheel snug inside the bell housing. A factory 2006 driveshaft connects the GMM Ripshift’d T-56 to the factory IRS, which house an Eaton Tru-Trac, 3.46 gears and the aforementioned BMR axles. A Harrop differential cover sits bolted to the back.

On the inside, it’s pretty much standard GTO, with the only additions being AutoMeter Cobalt gauges, an Aeroforce Interceptor OBD gauge and an upgraded stereo system that fills Joe’s ears with his favorite tunes, that aren’t emitting from his GTO’s soundtrack. We think we’d prefer the sound from the stroker LS1, though.

As it stands now, Joe has no immediate plans to turn up the wick any further on his cherished GTO — maybe a larger nitrous jetting, but that’s about it. He’s quite happy in the 10-second zone, and he can still enjoy the car on the street whenever he wants. We say that’s a win.

TECH SHEET:

  • CAR: 2004 GTO
  • OWNER: Joe Forsten
  • ENGINE BLOCK: LS1; (bored and stroked to 383 ci.)
  • CRANKSHAFT: Eagle, forged
  • PISTONS: MAHLE; forged
  • CONNECTING RODS: Eagle, 6.15 H-beam
  • CAMSHAFT: COMP Cams; hydraulic, 232/234 duration, 595/598 lift, 112 LSA
  • CYLINDER HEADS: Livernois Motorsports; CNC-ported, Stage 3 LS1 — Manley 1.55/2.02 valves
  • ROCKER ARMS: GM; 1.7 ratio
  • COMPRESSION RATIO: 11.8:1
  • INDUCTION: F.A.S.T. 92mm intake manifold, PTM 92mm throttle body, stock MAF sensor, K&N filter, OTR CAI
  • IGNITION: GM coil packs, MSD spark plug wires, NGK TR6 plugs, LPE ignition box
  • EXHAUST: Pace Setter; 1-3/4 inch long-tube headers, X-pipe, QTP cutouts, Magnaflow 2.5-inch diameter exhaust
  • FUEL DELIVERY: Lingenfelter 255/hr pump, stock regulator, 52-lb/hr injectors
  • OILING: Texas Speed LS6 ported pump, windage tray removed, oversized pickup tube
  • TUNING: Fasterproms; Jeremy Formato
  • TRANSMISSION: T-56;
  • CLUTCH: Monster Stage 3,
  • DRIVESHAFT: OEM 2006 GTO
  • REAREND: OEM IRS; 3.46 gears, BMR axles, Harrop differential cover, Eaton TruTrac
  • SUSPENSION: BMR driveshaft loop, cradle bushings, axles and drag bags, Pedders rear drag springs, KYB shocks (front), Koni adjustables (rear)
  • BRAKES: Stock calipers, DBA slotted rotors
  • WHEELS: OEM 18-inch 2006 GTO (powdercoated black)
  • TIRES: Nitto NT555
  • HP/TQ.: 515/543 (at the rear wheels)
  • E.T.: 10.75 at 129 mph
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Being infatuated with cars since he was a toddler, GM EFI Founder and Editor, Rick Seitz, has a true love and passion for late-model GM vehicles. When he isn’t tuning, testing, or competing with the brand’s current crop of project vehicles, he’s busy tinkering and planning the next modifications for his own cars.
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