Twin-turbo LSX-powered HQ Monaro

Holden did a ripper job when it designed the HQ Monaro coupe, but Mitch Godfrey made it even better thanks to a 1000rwhp LSX454 and elite-level finish

Photographers: Nathan Duff

While there were plenty of awesome cars designed in the 1970s, Holden’s HQ Monaro coupe has to be one of the top shapes to come out of the era of disco, fondue and bellbottoms. Mitch Godfrey’s Top 60 Elite-qualified Monaro didn’t start off as a stunner, but he turned it into a twin-turbo LSX454-powered, smoothed and slicked street car that packs a visual punch by enhancing what the factory gave us in 1972.

First published in the August 2019 issue of Street Machine

“I bought the car about eight years ago with a naturally aspirated small-block and an 80s-style interior,” says the Queensland fabricator. “After a couple of weeks I swapped in the L98 injected six-litre and F1R ProCharger from the Tonner I had before the Monaro to wake it up a little bit.”

Mitch cruised the coupe for six months, but while the side-mount sung a fine tune, it proved to be a bit too vocal for the street. “I sold the motor and ’box out of it because it was too loud,” he laughs. “It was cool, but too loud, so I put the coin into the LSX454.”

That’s about where the project took a turn, as Mitch started chasing tinworm, and the spectre of a whopping great snowball loomed large. “It looked good from far and was far from good, as the paint was thinning and there was a bit of rust coming through,” he says. “It’s the same old scenario; it snowballed into a full car resto.

“I started doing rust repairs in the shed while it was parked up, and that turned into a bare-metal respray with new door skins, new sills and new rear quarters. I had my mates in the shed half-charged on the Coronas and throwing up ideas like cutting and smoothing the bumpers, deleting lights and hiding parts.”

While we’ve seen plenty of hand-crafted, beautifully finished show cars that radically change what the factory delivered, what really makes Mitch’s coupe stand out is how he hasn’t chopped wildly into one of Holden’s best-ever styling jobs. He says he could actually restore the HQ back to standard to appease the ‘wrecked a classic’ crowd. “The biggest challenge was to not cut the car,” he says. “There are a few body mods like the tucked, boltless bumpers and shaved rear markers, but there are no tubs or rollcage, and everything uses the factory mounts and bolt holes. Even the dash uses the factory screw holes!”

Once Mitch had the shell looking slick, Erick Gonzalez at PJ’s Custom Spray Painting laid down the beautiful, smooth Dulux Custom Blue, before the project took a break.

But Mitch’s interest in the coupe was rekindled after visiting Summernats 31 as a spectator, and he dove into a 12-month thrash to get D ENEMY to Canberra just after New Year’s 2019. “The engine was sitting in there, but I didn’t have wheels, I didn’t have a diff, and there was a three-month fight to get the paddle-shifter. We were awake 36 hours straight to get there on time,” he laughs.

That engine is an LSX454 – 7.6 litres of Gen IV small-block considered by many to be the king of LS donks. Producing 627hp in stock aspirated form, Mitch’s makes over 1000rwhp thanks to a pair of Precision 6766 turbochargers.

“I bought the LSX454 as a crate motor. It is stock but they have six-bolt heads and a lot of good gear inside,” Mitch explains. “I wanted boost as I always wanted a street car that was a little tough. We did a trunnion upgrade on the rockers, but that’s about it. It’s a bit lazy of me I guess.”

A Holley Dominator EFI system fires L98 coils to ignite the E85 corn juice provided by a MagnaFuel 750 and Bosch 044 pumps. Cooling is sorted thanks to an Aussie PWR alloy radiator with twin 12-inch thermo fans, which sits behind the air-to-air intercooler.

After Summernats 32, Ricky Fenwick threw the blue beast on the hub dyno and squeezed 1112rwhp worth of juice out of it, despite only having 14psi and 14 degrees of timing in the tune. A three-speed TH400 auto and PTC 3500rpm converter handle all that snot, along with a Race Products sheet-metal nine-inch hanging out back chock full of good gear like 35-spline full-floater axles and 3.50:1 gears.

While that’s all A-grade stuff, the drivetrain is a bolt-in affair, as Mitch wanted to ensure the coupe can go back to stock if required. “Once you customise one thing you have to go through the whole car from bumper to bumper,” he explains. “But I wanted to work with the car and I didn’t want to cut it up. You can basically pull everything back out of that car and put it back to factory standard.”

After finally making it to Summernats 32 with hours to spare, Mitch was convinced by Mark ‘Happy’ Williams to try out for the Elite Top 60 after stumbling upon the Summernats 30 Grand Champ by chance. Mitch was rewarded with third Top Elite Coupe and an encouragement award; he even had a tilt at Grand Champion. But trophy-hunting isn’t Mitch’s thing.

“There’s always something you can improve on, and I could blow it apart and go again,” he says. “But it is a true streeter with over 2000km on it; it’s like driving a new Commodore.”

Just a heck of a lot cooler than a new car, Mitch!


Paint:Dulux Custom Blue
Brand:Chevrolet Performance LSX454
Induction:LS7 single-plane, custom elbow, 102mm throttlebody
ECU:Holley Dominator
Turbos:Dual Precision 6766
Heads:LSX six-bolt square-port
Camshaft:LSX 236/246 hydraulic-roller
Conrods:LSX forged 4340 steel
Pistons:LSX forged aluminium
Crank:Eight-bolt LSX forged 4340 steel
Oil pump:LSX454
Fuel system:Bosch 044 lift pump, MagnaFuel 750 main pump
Cooling:PWR alloy radiator, twin 12in fans
Exhaust:Custom headers, twin 3in system
Ignition:L98 coils
Gearbox:TH400 auto, Reid case
Converter:PTC 3500rpm
Diff:Sheet-metal 9in, full-floater 35-spline axles, 3.50:1 gears
Front:QA1 coil-over shocks, United Speed Shop Magnum arms
Rear:AFCO double-adjustable coil-overs
Brakes:HSV ClubSport R8 discs (f), Wilwood discs (r)
Master cylinder:Wilwood 11⁄8 in
Rims:Intro billet 18×7 (f), Weld beadlocked 15×10 (r)
Rubber:Dunlop 235/40 (f), Mickey Thompson 275/50 (r)

My wife Shelley Godfrey and kids Brianna and Chance; Jessie and Mandy; Erick Gonzalez at PJ’s Custom Spray Painting; Greg at GMC Auto Electrics; Dan’s Truck Detailing; Ricky Fenwick at Mr Holley EFI.