2005 Pontiac GTO - Devil In Yellow

Joe Mayhew's 2005 Holden Monaro Clone

Tony Whatley Jun 15, 2007 0 Comment(s)

When GM announced the end of production for the Firebird and Camaro in 2002, performance enthusiasts were left in a state of shock. There were many concerns about what GM would offer in the form of entry-level rear-wheel drive cars with a V-8 powerplant. The only remaining GM cars that fit the rear-drive V-8 platform were the expensive Corvette and some Cadillacs. Little did we know, but GM had a popular group of performance vehicles in Australia under the Holden name brand. In order to fill the missing void here in the US, GM quickly began planning to import the Australian Monaro. These cars have an excellent performance history and solid enthusiast groups in their home country, so GM decided to bring them here under the Pontiac flag as the new GTO. With a simple front fascia redesign and emblem changes, along with converting its production to the US left-hand drive spec, the cars were shipped to the States as an '04 model.

Joe Mayhew is a GTO man. His first performance car in high school was a '64 GTO, and later he restored a '67 with his father. While currently working as a parts manager at a Houston, Texas-area Pontiac dealership, Joe saw the first GTO on his lot. It was love at first sight: the car was a Yellow Jacket ("Devil Yellow" in Australia) automatic transmission '04. Joe adopted the Goat and took it home to his wife. The happy couple enjoyed it for a year, and then found out that the '05 models would be a little more potent with the introduction of the 400hp LS2 engine. They decided to upgrade to another yellow '05, but this time it was custom-ordered with a six-speed manual. Joe's wife liked the car so much, they later purchased another silver '06 GTO as her daily driver.

Intrigued by the Australian heritage of these cars, Joe decided to "restore" his car to Holden Monaro specs. As a parts manager with connections, he made a call to his friend Norm at Hunter Holden in Ryde, New South Wales, for the Australian parts. A Monaro VZ-style bumper cover replaced the Pontiac nose, and all Pontiac emblems were replaced with Holden emblems. Whereas two GTO 6.0L emblems originally sat on the front fenders, now sits a pair of Australian-spec side-marker lights, like the Monaro's. The rear trunk initially featured the huge GTO spoiler, but that was removed and the holes were filled in and painted over. Joe had his friends over at First Collision in Baytown, Texas, do the color-matching paintwork. For the interior, a custom Monaro gauge panel and pod gauges were installed, along with Holden emblems on the steering wheel and doorsill plates. To match the attitude of the car, a set of Australian-made ROH 18-inch Drift-R wheels with black centers were added as well. These wheels showcase a set of painted PBR brake calipers and DBA 4000XS drilled brake rotors.

In order to ensure that the performance of this Monaro could keep up with its aggressive appearance, Joe enlisted the group at Horsepower Engineering in Houston, Texas, for several upgrades. They decided to go with the popular 238/242 HPE S-Cam as a replacement for the factory bumpstick, and to help the engine exhale more efficiently, the car was outfitted with a long-tube header and exhaust system by Stainless Works. A Lingenfelter cold air intake was installed, which feeds the intake charge through a ported 90mm throttle body and a FAST 90mm composite intake manifold. The belt-driven accessories are turned a little slower with the addition of an SLP crankshaft pulley, which produces more horsepower. This combo still uses the factory LS2 short-block and non-ported heads, but yields an impressive 451 SAE horsepower and 419 ft-lb of torque at the rear wheels. To date, the car has run a best of 12.50 at 115.5 mph in the quarter-mile, with mad wheelhop due to the independent rear.

Joe didn't build the car for the dragstrip, and he is quite content with surprising unsuspecting victims on the highway. The car is an all-around street performer that handles, brakes, and accelerates comparably with some of the most feared performance vehicles on the road. It still has excellent road manners and all of the fancy comfort options included. Joe always gets a kick out of walking a would-be competitor on the street, leaving them with the thought, "I got beat, but I have no idea what that was!"

Data File 2005 Holden Monaro Clone/Pontiac Gto

OWNER: Joe Mayhew, Beach City, Texas
BLOCK: 364ci OEM LS2, aluminum
HEADS: Non-ported OEM LS2, Patriot valvesprings
CAM: HPE S-Cam 238/242, .608/.612 lift, 115 LSA
PUSHRODS: COMP Cams chrome-moly
ROCKER ARMS: OEM roller body
PISTONS: OEM hypereutectic cast-aluminum flat-top
RINGS: OEM low tension
CRANKSHAFT: OEM 3.62-inch, cast steel
RODS: OEM cast
THROTTLE BODY: HPE ported OEM electronic 90 mm
INTAKE: FAST 90mm manifold, Lingenfelter cold air intake
FUEL PUMP: OEM in-tank
IGNITION: OEM coil-on cylinder, NGK spark plugs
ENGINE MANAGEMENT: OEM computer with custom HPE dyno tuning
EXHAUST SYSTEM: Stainless Works 1.75-inch long-tube headers, Stainless Works Catback
CLUTCH: GM Corvette LS7 Z06 clutch, single disc
TRANSMISSION: Tremec six-speed manual with GMM Ripshift shifter
DRIVESHAFT: OEM multi-section
FRONT SUSPENSION: OEM coil-on strut, independent
REAR SUSPENSION: OEM independent rear
REAREND: OEM housing with Harrop support brace and OEM 3.46 gear ratio
BRAKES: PBR calipers with DBA 4000XS drilled rotors
WHEELS: ROH Drift-R 18x8 front (41mm offset), 18x9 rear (50mm offset)
FRONT TIRES: Toyo Proxes T1-R 245/40/ZR18 (97Y)
REAR TIRES: Toyo Proxes T1-R 275/35ZR18 (99Y)
FUEL OCTANE: 93 octane
RACE WEIGHT: 3,950 pounds
BEST ET/MPH: 12.50 at 115.5 mph (prior to FAST intake and LS7 clutch)
BEST 60-FT TIME: 2.16 seconds
CURRENT MILEAGE: 12,545 miles


Check out Joe Mayhew's 2005 Pontiac GTO with PBR Brakes and Toyo Proxies Tires, Featured in the 2007 August Issue of GM High Te...
Tony Whatley Jun 15, 2007


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