Video: 615-cube no-prep HT Monaro

Justin Simpson's HT Monaro is a stunner, but also packs massive cubes and plenty of nitrous in the quest for no-prep glory

Photographers: Mitch Hemming

Justin Simpson is not a man who does things by halves. Whether it’s running his incredibly successful Brisbane-based performance tuning company, Horsepower Solutions, or as co-promoter of the successful Kenda 600 Radial series, he gives it his all. So, when he unveiled his stunning 1969 HT Monaro at Street Machine Summernats 34, it’s safe to say it was a show-stopper.

The HT is both a fine show car and a hell of a race car; it’s also Justin’s first car, purchased when he was just 16 years old. Since then, it has won numerous drag racing events in Super Sedan, Super Stock and Nostalgia. It then sat on a hoist for six years before being relaunched as a serious no-prep contender.

“It’s hard to remember all the combinations that car has had,” Justin laughs. “We ran constant-flow mechanical injection on an old 468-cube, iron-headed big-block Chevy, then slid a 540-cuber into the car, initially on mechanical injection before moving to twin carbs.”

Justin’s next move with the HT was into Super Stock A/Gas warfare with twin carbs and nitrous, running in the 8.30s, later adding EFI with a Haltech Platinum ECU and wet nitrous kit to run flat 8.00s.

It all went pear-shaped back in 2017 when he kicked a rod out at the Winternationals. Justin took the HT back to work and stuck it up on the hoist.

“At the point we wrecked it, we had the car into the 7.60s at 178mph with an air-shifted Lenco trans with a Crower slider clutch,” he recalls. “That was, without doubt, the most fun you could have in a car, but the work on the clutch – you just can’t do that to your team!”

Fortunately, Justin had already been accumulating parts for a 615ci combination that had been on the whiteboard since 2016. “In August 2020, I figured it was time to get the car back up and running, so we pulled the old rodded motor out with the intention of giving the engine bay a freshen-up. The plan was essentially to get rid of the pop-riveted aluminium panels in the firewall and go to a full weld-in panel, change the front struts, and just bring the car into the 21st century.”

Even though the HT has been a race car for 30 years, it’s still nearly all steel, including the roof, quarters, front floorpans and doors. Only the front clip had been replaced with fibreglass.

After re-mounting the struts and adding a new mid-plate, Justin focused on upgrades inside the car.

“The rollcage never fitted me, and I knew how fast the car should go with the new motor, so we cut the ’cage at the back hoop, leaving the main hoop in place and essentially building a new funny car ’cage in chrome-moly that fitted me correctly.

“Dan Swanney, who used to work out of my shop as a fab guy, has always done my work, and we just got stuck into it after work each day. There was a lot of small stuff to fix, like the windows that we’d installed back in the never-never with just rubber jammed in behind the Lexan. These were all yanked out and replaced with Tin Soldier flanged window frames that look trick.

“When we finally got all the fab work finalised, I was just going to touch up the paint, and we know how that goes.”

Paul Butler and Jeremy Platt from Concept Paints tag-teamed on a completely new paintjob, removing the old 1980s stickers, getting the bodywork just perfect and laying on Justin’s custom-blended version of Holden’s Hothouse Green.

“I know it’s a race car, but I wanted the Monaro to look as close to the factory HT GTS styling as possible,’ Justin explains. “Stickers were replaced by painted stripes, Chris Bool from Kipart Signs did a beautiful job of airbrushing the front grille, and a new badge kit from Rare Spare completed the job.”

Under the car, it’s all business, with Strange front struts and Afco rears, re-valved to suit no-prep. The rear end was upgraded to a Race Products 40-spline floater with a Strang Ultra Case, anti-roll bar, and Weld 15×15 double-beadlock rims wrapped in 33×16.50-15 slicks.

A chrome-moly driveshaft connects the rear end to the Hughes Pro Mod Powerglide, which has been fitted with a dump valve (even though Justin won’t need it) and a Hughes bolt-together converter with spare stators to suit track conditions.

The 615ci Chevy up front is a monster. The Dart block houses a Callies steel crank and GRP alloy rods, topped with Big Duke 18-degree heads and intake, along with three stages of Induction Solutions dry nitrous. Cam specs are undisclosed, but we’re told there is more than an inch of lift. The engine will belt out around 1200hp naturally aspirated, with another 600hp to be had from each nitrous kit.

Justin says he went to nitrous over turbos because of the extra tuneability it allows.

“I had a turbo kit for this car years ago, but nitrous is a bit of a dying art. For no-prep racing it’s still the quickest, and it’s good to be different,” he says.

“I tune for a living and I’ve had my hands on every ECU known to man,” he continues. “Fitting a Haltech Nexus is just an absolute no-brainer for both a tuner and car owner. Haltech offers the best tech support and after-sales service of any company in the world, in my opinion. Forget the rest; there is no comparison.”

As far as sensors and datalogging go, this car has it all – EGT, O2, driveshaft, wheel, shocks, laser ride height – as well as the new Haltech dash with keypad.

“I can’t wait to get behind the wheel,” Justin says, before adding that his work commitments mean he has limited opportunities to test the car. “Gup [Powercruise promoter Michael Gilbert] has an event coming up in September, and we can’t wait for the upgrades to finish at Warwick as well; I see that as being the new home of no-prep.”

So how quick will it run?

“Initially, we will hit the track with all three kits loaded with around 400hp in each,” Justin says. “This will give us around 2400hp, and we should go sixes at 200mph plus.”

Regardless of what the Monaro runs, it’s awesome to see another car being added to the fleet of serious no-prep cars in Australia. The fact that Justin is an all-out turbo tuner and has gone nitrous instead adds another exciting dimension to this stunning build, and given his track record for building and tuning, this thing will be bad-arse.

Justin would especially like to thank his wife Lauren; crew chiefs Connor and Liam; PB Automotive; Concept Paints; Performance Wholesale; Wellpro Racing; Haltech; Hughes Transmissions; Horsepower Solutions; Suspension Dynamics; Promodz Fabrication; and his mates Sauer, Bood, Grums, Timmy and Clint.