LS3-powered custom 1972 Holden HQ Monaro GTS – flashback

Looking back on Karen Keves's iconic custom HQ Monaro dubbed Marilyn

Photographers: Easton Chang

RATHER than kick things off by sifting through an endless list of insightfully prescribed and exquisitely executed modifications to Karen Keves’ HQ coupe Marilyn, let’s instead start by pointing out the elements of the car which still remain standard. They are, in no particular order, the lower door hinges, the side glass and the headlight dipper switch. That’s it.

This article on Karen’s HQ Monaro was first published in the October 2011 issue of Street Machine

That an iconic car like an HQ Monaro can be so magnificently messed with yet still remain true to the stunning silhouette which endeared her to it in the first place is a credit not only to Karen, but also her husband Tom and the man responsible for the work, metal magician Chad Ackland at Xtreme Restorations. It’s the result of an exhaustive three-and-a-half year build fraught with trial, error, tribulation and finally triumph, but as Marilyn Monroe herself was once heard to say, “If you can’t handle me at my worst, then you sure as hell don’t deserve me at my best!”

Camaro driving lights are integrated into the front bar and beaver panel. Billet surrounds are larger (and shinier) than original units. Headlights house integrated front indicators. Gorgeous one-off hand-built billet grille replaces standard HQ plastic egg-crate

Marilyn (the car) was certainly looking her best when the sheets were yanked off her at Meguiar’s MotorEx. But that was in fact her second unveiling, and this time she at least had the decency to put some clothes on. Her popular in-the-raw debut at Summernats 24 won her a lot of fans, but soon thereafter she was completely dismantled in preparation for Motorex.

Chad made up the neat tail lights from LEDs, diffusers and perspex. The bumper sits higher than standard to close up between it and the bootlid. Neat alloy drop tank holds 60 litres of 98 octane pump gas

“It was absolutely heartbreaking to pull the car apart again, especially after driving it, but by taking it to Summernats we were able to show everyone the extent of the metalwork involved,” says Chad.

“Getting it ready for Summernats was a lot of work, but it was worth it,” adds Karen. “It gave us the chance to make a few changes and fix a few things.”

The HQ won the Gold Champion Medal for driveline and undercarriage at MotorEx. Custom-built floorpan boxes in the hand-built chassis, with swage lines running from front to rear. Not a single factory suspension or chassis component remains in the car

Of course, the most dramatic change since we saw it last (SM, May ’11) is the oh-so-subtle matte silver paintjob with orange highlights, but more on that later. For now, let’s take a look at the mind-numbing scope of the modifications. Starting from the ground up, the entire chassis is bespoke with mandrel-bent rails, a custom-built four-link rear, Winters quick-change 9in diff, a Rodtech front end with tubular A-arms and Air Ride Shockwave bags at all four corners.

The interior features a hand-built sheetmetal dash which flows seamlessly into both the door trims and a full-length console, which in turn gracefully integrates into a hand-formed steel parcel shelf. Even the gauges feature custom “Marilyn” lettering, and the seats are from HSV’s Grange, no less. There are over 100 individual body mods, from the extended sills to the flush-fit glass and everything in between. Dig the 22in wheels? Us too. They are a large-window version of Intro’s West Coast rim and are the first set to appear on a car anywhere on earth, with Showwheels giving Karen first bite at the cherry. By now you start to understand that Marilyn is a no-expense-spared kind of girl. And while she’s irrefutably unique, charmingly curvaceous and more than a little sassy, she still carries herself with all the grace and dignity of her 1950s namesake.

The engine bay sheetmetal is smoothness personified. The LS3 looks a treat, with Pro Flo manifold, smoothed block and heads painted Galaxy Grey, HK-style Marilyn badges and electric water pump

That being said, she ain’t just a pretty face. Marilyn is motivated by 6.2 litres of Chevrolet’s finest – an LS3 courtesy of some poor unfortunate bugger who stacked his current model HSV. His loss was Karen’s gain, but not a big enough gain for her liking, so the engine was treated to a Howards hydraulic roller cam of 216 degrees duration and 550 thou lift, along with a custom eight-throttle body Pro Flo inlet manifold which is pure muscle car porn. With upgraded injectors in place and the Autronic ECU tuned to perfection, the engine spat out 550 neddies, representing gains well in excess of 100hp.

Just like the cabin, the boot is trimmed in Italian leather, matching the orange highlights on the body. The compressor, tank and valves for the airbag system are hidden behind the trim panel

Performance aside, the engine is a pleasure just to look at. With all their ancillaries, sensors, coilpacks and fugly plastic intake, it’s difficult to make an LS engine look even remotely presentable. But Chad and Paul from Pro Flo combined their wealth of skills and resources and the result is sensational.

Besides the sheetmetal dash flowing beautifully into the doors, centre console and parcel shelf, the interior features a heap of little tricks, including Marilyn-branded Classic Instruments, push-and-pop glovebox lid, late-model Camaro air con vents and Wilwood pedals

The time invested in linishing the cast marks from the block and heads alone is confronting, but consider the hours involved in those custom billet bonnet hinges or the hand-formed scalloped firewall, swooping inner guards and beautiful custom radiator shroud, all of which forms one single piece, together with the front guards and nosecone.

“The big thing with the engine bay was that we wanted it to look different,” said Chad. “We didn’t want to have plain, flat panels, and that’s why we went with the recess in the firewall and the curved inner guards.”

While the bulk of the fabrication work was done prior to Summernats in January, stripping the car to nothing, finishing it off, painting every square inch and reassembling it prior to MotorEx in July was a hell of a mission.

Neat centre console hides the airbag controls and gauges, headlight switch and power window buttons

“The basic shape of a car comes together pretty quickly, but the amount of time you spend on fine tuning the little details is crazy – that’s what really takes the time,” says Chad. “The undercarriage panels didn’t exist at Summernats, so we had to build that first. There were a lot of little bits and pieces to finish off, like fabricating the lid and lever for the brake reservoir under the cowl panel, making the bonnet and boot latches and fitting the speakers to the speaker grille. We also re-did the firewall with a different shaped scallop.

“We then made the radiator cover, and fabricated the support underneath the radiator. I welded right around the bonnet to close up the gaps, and then made up a gapping tool and went right around the car to make sure that they were spot on 4.5mm everywhere. With paint it’s probably a little less now.”

Because the car has a custom floor and dash, Flaming River column and HSV Grange seats, Chad and trimmer Steve Baum at Statewide Trim had to start from scratch with the cabin layout. “It was a big challenge,” says Chad. “We had to get the driving position right and pretty much build everything around that”

Xtreme Restorations’ Josh Janetzki laid on the colour, a superbly understated blend of House of Kolor Orion Silver and Galaxy Grey with Nova Orange highlights, overlaid with Saturn Klear for a sweet matte finish.

“I think some people were surprised by the colour,” says Karen. “It’s very different to what we originally had picked. We spent a lot of time trying to figure out which way to go and we always ended up reverting back to when the car was at Summernats in bare metal, which is where the silver came from.”

Chad has his own reasons why the matte finish works so well.

“The car had so much detail that a fancy paint job would’ve taken the eye away from all the subtle things and I was very familiar with that type of finish from my time at Rad Rides in the US.” he says.

Needless to say, Karen is justifiably chuffed with the finished product.

“Marilyn has become a custom car I am extremely proud of, and I can hardly believe that I have had the opportunity to do it,” she says. “My Marilyn is my dream, my mark on the car world. With her beautiful shape, curves, style and class, there was no one like Marilyn Monroe, and I feel that there will never be another car like my Marilyn.”


  • Nip and tuck: Steel bumper bars were sectioned, shortened and incorporated into the bodywork
  • Hot flush: Flush fitting front and rear ’screens achieved by raising the surrounding metal
  • Shaved: Roof gutters, external door handles and locks removed
  • Pretty yet practical: Tops of door skins built to roll up onto the top of the door for a clean look, whilst still retaining side glass
  • D-cup bonnet bulge: Reduced from the original design plan’s DD-cup at Karen’s request!
  • Nose job: Nosecone sliced, extended down 55mm and blended with front guards
  • Short skirts: Sill panels dropped 20mm closer to the deck to make the car look even lower
  • Dulcet tones: Exhausts exit through finely sculpted portholes in either sill panel


Colour: HOK Orion Silver/Galaxy Grey mix

Brand: GM 6.2L LS3 V8
Induction: Pro Flo custom 8 throttle body inlet manifold
Camshaft: Howards hydraulic roller 216/550
Preferred fuel: 98 octane pump
Fuel system: Siemens 646cc injectors, Autronic ECU
Cooling: Custom alloy radiator, electric water pump
Exhaust: Modified ceramic coated Di Filippo headers, twin 3in stainless steel system with Magnaflow mufflers

Gearbox: Tremec 6-speed manual
Diff: Winters quick-change 9in, 4.11:1 gears

Front: Fabricated rails, Rod Tech front end, tubular A-arms
Rear: Mandrel bent chassis rails, custom built four-link
Airbags: Air Ride Shockwave
Brakes: Wilwood discs and four-piston calipers, 14in (f), 13in (r)
Master cylinder: Wilwood remote
Steering: Flaming River rack and column

Seats: HSV Grange, customised (f), custom seat frames and padding (r)
Wheel: Billet Specialties
Mods: Fabricated dash, parcel shelf and console
Trim: Italian leather
Instruments: Classic Instruments gauges, custom lettering
Shifter: Tremec
Seatbelts: Lap belts recessed into seat
Carpet: Custom suede-wrapped fibreglass floor
Stereo: Kenwood source unit and rear speakers

Rims: Showwheels custom GTS replicas, 20×8.5 (f), 22×10 (r)
Rubber: Nexen 225x35ZR20 (f), 265x30ZR22 (r)

I would like to thank my husband Tom so much. Without his support, guidance and love my dream would not have come true. Chad Ackland and Josh Janetzki at
Xtreme Restorations, Steve Baum at Statewide Trim, Paul Sant at Pro Flo Performance, Peter Lamb at Melomotive, Chris at Showwheels, Owen Webb