Mario Busljeta remembers the exact moment he was inspired to build a wildly overpowered street machine. It was back in December 2019, when he saw Daniel Szabolics’s insane HQ Monaro on the cover of Street Machine. His eyes were suddenly opened to the possibilities.

First published in the February 2025 issue of Street Machine

“I thought, ‘Shit, a street car with that kind of horsepower would be neat!’” Mario exclaims. “Initially I wanted to build an HZ wagon; I even bought the car. But my sons David and Marinko, and Andy and Damo at Adelaide Motorsport Fabrication, convinced me that doing all the chassis and fab work to something so plain wasn’t the right idea. They encouraged me to build a muscle car, so I bought an HQ Monaro.”

The coupe Mario bought was already a stout streeter. It had been freshly painted in the silver-and-orange GTS combo that so many Queys rock, and boasted a twin-turbo big-block under the bonnet.

“I drove it around for a few weeks, knowing in the back of my mind that we were going to build it into something more serious,” Mario says. “In that time, I got so sick of the hot air from the turbos in the engine bay coming out through the cowl scoop, across the windscreen and in through the windows.”

Thankfully for him, the team at Ad Mo Fab had a solution. “I called in to see the car one day and the boys had done the rear clip,” Mario recalls. “I took a look under the car, saw how much room had been opened up and knew immediately we were going to rear-mount the turbos.”

The twin 94mm Precision war whistles were placed underneath and out of sight, way back near the diff. “It might be a little laggier than if they were in the engine bay, but I love having the heat out from under the bonnet,” says Mario.

So inspired was Mario by the BOLICS Monaro that he reached out to its engine builder, Frank Marchese at Dandy Engines, for help with his big-block build. Using a Dart Big M block, Frank punched the capacity out to a very capable 540 cubes and a modest 10.5:1 compression ratio. A custom-ground tool-steel roller cam conducts the chaos, with the short motor capped by Higgins-fettled AFR 20-degree heads and a Plazmaman billet intake manifold.

By virtue of the remote turbos, the engine bay is particularly sparse, which allowed Mario and the team to construct beautiful headers rather than tantrically tangled turbo manifolds, making access to the sparkplugs a breeze. The roomy bay really allows you to take in the magnitude and quality of the fab work, right down to the attention to detail with the wiring for the FuelTech FT600 ECU and supporting electronics.

MPW Performance handled the installation of the engine, wiring, plumbing and initial set-up of the car. MPW’s Adam Rogash has continued to assist as Mario learns the difference between his 11-second ClubSport R8 and the seven-second Monaro.

“I don’t think Mario knew what he wanted initially!” says Adam. “He knew he wanted a fast street car like Daniel’s Monaro, so he enlisted us to help him with that goal, and the car has already proven itself, running 7.1@199mph.”

As the builder of some of the country’s quickest street cars, Adam understands better than most the various challenges in trying to get a full-weight street car like Mario’s HQ down the track. “It’s over 4000lb, and for a race car, ideally you’d have it as light as possible,” he says. “To counteract this, we just make bucket-loads of power and really lean on the torque management curves in the FuelTech software.”

Putting the car on a diet and removing things like the trim or other creature comforts could help see it into the sixes, but Mario was insistent that the car race as it was going to be driven.

After the MPW crew had finished assembling and detailing the Monaro, Frank Marchese loaded a tune into it and ran his fingers over the keys during a dyno-tuning session. “Frank got over 2970hp and wanted to keep going, but I reminded him that I still had to learn to drive the thing,” chuckles Mario, who is still getting used to having all that power underfoot.

Adam has been the man pedalling the coupe to some of its best performances, while coaching Mario as he spends more and more time in the captain’s chair. “The first drive was a little nerve-wracking!” Mario admits. “I wasn’t used to racing in a fire suit or full-face helmet, so it was pretty hot. But the boys have made the startline procedure so easy. All I’ve got to worry about is the transbrake and the bump button, and remember not to be scared to go full-throttle!”

And while the Monaro is enjoying a baptism of fire, laying its best times at The Bend and Sydney Dragway, Mario has his sights fixed on getting it engineered and then clocking up the street kays. But don’t confuse this with plans for Drag Challenge domination.

“Drag Challenge might beat it up a bit too much! We’re building a 1500hp HT Monaro with Adam and that’ll likely be a Drag Challenge car,” says the man with one of the country’s
wildest garages!

MARIO BUSLJETA
1971 HOLDEN HQ MONARO

THANKS
Andy & Damo at Ad Mo Fab for all the fabrication work and long nights; Frank at Dandy Engines for building the motor exactly the way we discussed; Adam at MPW for finishing off the car’s wiring, installing the computer, and all the help at the track; Timmy for building the diff; my sons David and Marinko for all their support; my queen Tanya for all her love and support; and to anyone who has worked with me on the HQ, you know who you are – thank you! You have all become my good friends.