While the GT3 racing class is awesome, it may leave a little to be desired for street machiners like us. After all, current GT3 cars are based on today’s road-going supercars – no old-school metal in sight!

First published in the April 2022 issue of Street Machine

But what if the rules were bent to allow GT3 cars to be built on older platforms? This is exactly what Richard Shumack thought while watching the Bathurst 12 Hour race, with GT3 classes occupying a good chunk of the grid. “After watching the Bathurst 12 Hour, I came to the conclusion that Australia needs a homegrown GT car,” he says.

“Because the car would have to be completely made from scratch, I thought, why not bring back one of the best-looking Holdens ever made: the HQ Monaro?”

I immediately fell in love with Richard’s idea of kitting out the HQ’s iconic shape with radical aero and modern smarts, and got started with the shell before getting stuck into the exciting modifications.

Since the majority of GT3 cars run flush-mounted glass, I figured the HQ needed that to look the part, and it would also likely gain aerodynamically from the change. With the new body having to be made from scratch anyway, I modified the A-pillar, front screen cowl and window surrounds to accommodate flush-mounted polycarbonate windows, and pushed the side windows outwards slightly for better airflow around the sides of the car.

Being a GT3 car, a beefy flare kit and extensive aero package was a necessity. I made sure I retained as much HQ styling as possible in the new bodywork, especially the side bodylines and guard flutes. After widening the track width to match that of most GT3 cars and positioning a set of GT3-spec wheels wrapped in Michelin slicks to suit, I duplicated and offset the front guards and quarter panels as the base for an open-flare design, with intakes in the front and vents in the back.

Due to the lowered stance and chunky rubber, I had to raise the wheelarch over the top of the side bodylines to ensure the wheels remained accessible and easy to change. Incorporating such a large opening into these iconic lines was shaping up to be a challenge, so I looked around for inspiration on how it could be achieved.

The Roadster Shop’s second-gen Camaro race car build, ‘Rampage’, does this perfectly with its wide-body flare kit (although the Camaro’s side bodylines are not as pronounced as the HQ’s), so I integrated a similarly shaped wheelarch into the existing flares and mimicked the shape of the Camaro’s rear opening of the quarter flares, too. I then modelled the side skirts, tucking them under the car at the front and blending them into the rear wheelarch at the back.

The front end had to remain unmistakeably HQ while incorporating various intakes and aero additions. I began by smoothing out the front bar and deleting the indicators and number plate recess. I created custom intakes to replace the holes at the centre of the factory bar and did away with the factory lower front valance.

Drawing further inspiration from The Roadster Shop’s ‘Rampage’ Camaro, I modelled the front splitter and lower ‘mouth’, complete with an insert that directs air into brake cooling ducts at the sides. Modern aftermarket LED headlights replace the factory units.

At the rear, a huge wing was the first addition, as well as LED tail-lights and a diffuser. Most GT3 car diffusers are all function and no form, but I wanted this one to suit the HQ, so I notched the centre of the diffuser in line with the rear plate recess, as well as curving the outer corners and adding a subtle lip around the edge of the beaver panel.

With the majority of the bodywork and aero completed, I set about adding finer details to the Monaro. AeroCatches have been recessed into the bonnet and bootlid to ensure they stay put, and central bonnet vents have been added to rid the ’bay of excess heat, while vents at the top of each guard allow high-pressure air to escape from inside the wheelarches.

The cabin is decked out with the appropriate rollcage, steering wheel and race seat, and a fuel filler now resides in the driver’s-side quarter window.

As the panels of GT3 cars are primarily carbonfibre, I decided it’d be awesome to leave it exposed on the HQ. Tim Pattinson of TP Race Design put together some neat graphic elements to break up the carbon, including a set of GTS stripes, which I applied over the top in dark tinted clear.

Along with the tow point decals, Tim dreamed up a ‘GT3’ logo in the original ‘GTS’ font to go under the guard flutes and in the rear plate recess, which is a really cool touch.

Imagine this thing tearing up Mount Panorama at the next 12 Hour against a field of modern track-spec supercars! How’s that for a homegrown GT car?

IN DETAIL:

• GT3-style Aero package
• Wide-body fender flare kit
• Carbonfibre body
• Flush-mounted polycarbonate windows
• GT3-spec wheels, tyres & brakes

Got a cool idea for a build that you’d like to see brought to life in Expression Session? Email us at [email protected] with a detailed explanation.