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Blown 400-cube custom 1973 Holden HQ Monaro - BANG ON

By Andrew Broadley | Photos: Chris Thorogood, 15 Jan 2019 Features

Blown 400-cube custom 1973 Holden HQ Monaro - BANG ON

Shaun Horton took one of the most epic show cars in recent memory and elevated it to the next level in just 18 days

This article first appeared in the December 2018 issue of Street Machine

SHAUN Horton’s wild HQ Monaro just goes to show that a good thing can always be made better. You very likely recognise the Quey’s distinctive, low-slung silhouette from its initial incarnation, CHOPPT, built by Jody Vincitorio. Back then the car ran a 468ci big-block with Crower stack injection, HOK Emerald Green paint and a crazy bare-metal and croc-skin cabin that showcased Jody’s flawless metalwork skills.

Holden HQ Monaro rearBANG-ON sits incredibly well, accentuated by the low roof height. Huge tubs in the rear accomodate enormous 20x16in Mickey Thompson wheels, each of which was carved from a single billet of aluminium. Air Ride ShockWaves allow for the groundhugging stance when deflated

Under Jody’s stewardship the car featured on the cover of our February 2012 issue and made the Summernats Elite Top 10 twice. It was an exercise in unbridled creativity and never masqueraded as a street car, meaning that it didn’t have to please any engineers or comply with any bastard Australian Design Rules. All it needed to do was be tough as hell and look amazing, two things it did exceptionally well.

Holden HQ Monaro sideAs it turns out, Shaun and Jody are good mates, and Shaun kept close tabs on the Monaro’s initial build and developed a real fondness for the car. “I used to call into Jody’s shop on my lunch break at least once a week when he was building the HQ,” he explains. “I loved the car, and I always wanted to own something that wild, but never had the time to build it.”

Read next: Blown big-block HQ Monaro GTS

Shaun got his chance years later when he heard that Jody was keen to find a new home for the Monaro. Jody had given it a birthday, respraying it orange and blacking out much of the previously polished hardware, including the epic 20x16in Mickey Thompson wheels. Subsequently, he’d yanked the injected big-block and shuffled the Monaro into a darkened corner of the workshop.

Holden HQ Monaro frontShaun had relocated to Queensland in the years since his visits to Jody’s shop, but having lusted after the car for so long, he wasted little time in strapping his blown, alloy Donovan-blocked 400ci Chev to a pallet, shipping it to Shepparton, and flying down to buy the car and resurrect it in Jody’s barn, before dragging it home.

Watch next: Slammed custom Holden HQ wagon

While the extensive fab work and wild body modifications on the car remain largely unchanged from the initial build (read more, below), repowering and re-plumbing it and getting it back into show-worthy condition was a massive job, and one that Shaun and his helpers managed to accomplish in an 18-day thrash.

Holden HQ Monaro rear“We ran all new brake lines and braided fuel lines, installed a new flat timber floor and smoothed, painted and fitted new seats, and made a custom shifter,” Shaun says. “The car never had any back brakes, so we fitted those, and resprayed the front of the car while it was there.”

Read next: Blown Holden HQ 'Terminator' Monaro

Everything was done to an exacting standard; there were 300 hours involved in deburring and polishing the block and heads alone! “We started with a die grinder, then filed, sandpapered and polished it,” Shaun explains. “We did it while it was assembled with all the orifices taped up – it was a mission! Even underneath it where you don’t see it’s polished. We linished 5mm off the edge of the timing cover so it sat flush with the block. We had the skin off our fingers by the time we were done sanding in all the little grooves.”

Holden HQ Monaro engine bayThere are flowing lines everywhere you look in the engine bay, from the way the firewall rolls into the body to the beautiful curved profile of the radiator support. The engine itself is a blown, all-alloy small-block Chev that’s been polished to within an inch of its life. It’s pretty as hell, but still good for 1200hp

The engine itself is a serious piece of hardware, based on a Donovan alloy block topped with AFR 245 alloy heads. Built by Sandy Graham, it runs a .750in solid-roller camshaft, JE slugs, a Scat double-keyway crankshaft and Oliver rods. With a billet TBS 6/71 blower supplying boost and an Enderle Bird injector hat distributing methanol, the combo is worth around 1200hp – enough to turn the steamroller-like 31x18.5x20 Mickey Thompson hoops with relative ease. “It’s virtually a drag car motor in a show car,” says Shaun.

Read next: SMOTY-winning 454-cube HQ Monaro - RAT ATTACK

Holden HQ Monaro engine bayA big focus of the overhaul Shaun orchestrated was making the car more usable, fitting things like rear brakes, an alternator and a more practical interior. He and Paul Musty from Shepparton Motor Trimmers worked late nights for a week to install a flat timber floor in the car, and trim and fit-out the cabin. Plastic drag car seats were painstakingly smoothed, then painted in candy two-pack and fitted up. Billet Specialties interior door handles and steering wheel were used, and an alloy spacer was fitted to the base of the steering column to tidy that area up further.

Holden HQ Monaro engine bayAdding more complexity to the process, Shaun was keen to return the polished finish to all the hardware that had been blacked out. That meant the wheels, radiator, fuel tank and other components all had to be removed, stripped, rubbed and polished. “The etch primer had eaten into the alloy in spots, so that took bulk hours,” he says. “It’s a big job when you’re going to show it and it needs to be perfect. Every bolt on the car is button-head stainless and has been polished.”

Holden HQ Monaro interiorThis car’s cabin has evolved a great deal since it first hit the scene. Shaun was keen to make the car more usable for events, so he fitted a trimmed flat timber floor instead of the cleared bare-metal job that it once had. Plastic drag-car seats were smoothed and painted in candy, with an additive to prevent the paint cracking when the seats flex. The beautiful, full-steel dash and Dakota Digital instruments remain, and still look brilliant

It might have been a painstaking process, but one that proved worthwhile when the Monaro returned to the winner’s circle at Summernats this year, picking up Top Super Street as well as a High Impact Award and a Top 20 spot in the Elite Hall. Shaun also had a crack at Grand Champion, making it into the Magnificent Seven and proving that as wild as the car is, it could be competitive in driving events.

Holden HQ Monaro interiorWith the Quey complete, Shaun is set to knuckle down on an FB sedan build he has on the go. He has serious form in this department, with a blown small-block FB wagon of his having graced the cover of Street Machine back in the day. “I’m doing the chassis at the moment,” he says. “It’ll have full rails from front to rear, an adjustable four-link and airbags. It’s a full rotisserie build with flat floors; a show car that can be driven on the street. Every car I’ve had has had at least 1000hp and been blown alcohol. This one I want the same power, but all under the bonnet. The idea I have at the moment is for a NASCAR-style motor with the cubes pumped up and more compression – a high-revving naturally aspirated combo.”

Holden HQ Monaro dashSounds like something we might be interested in!

METAL MASTERY

Holden HQ MonaroIt still retains that unmistakable HQ coupe shape, but the Monaro’s body has been extensively modified. “It’s basically a full custom, hand-made body,” Shaun says. “There’s the roof chop, and the floor, firewall and dash have all been cut out and re-made. The car has two floors – one that the seats bolt to, and another smooth one so you can’t see the seat bolts from underneath. All the wiring and plumbing is routed between the two floors, so it’s all hidden. The bootlid opens to the side, and the boot area and underside of the bootlid are decked out in custom sheet metal.”

SHAUN HORTON
1973 HOLDEN HQ MONARO

Colour: Tangerine Orange Candy

ENGINE
Brand: 400ci Donovan aluminium small-block Chev
Induction: The Blower Shop intake manifold, Enderle Bird injector hat
Blower: TBS 6/71, TBS large-port manifold
Heads: AFR 245cc, CNC-ported
Camshaft: Solid-roller, .750in lift
Conrods: Oliver
Pistons: JE
Crank: Scat, custom twin-keyway
Fuel system: Enderle 80A-00 fuel pump
Radiator: Aussie Desert Cooler
Exhaust: Custom
Ignition: MSD 6AL

TRANSMISSION
Gearbox: Two-speed Powerglide
Converter: Dominator custom converter
Diff: 9in, 3.7:1 gears, 31-spline Moser axles

SUSPENSION & BRAKES
Front: Air Ride ShockWave
Rear: Airbags
Brakes: Wilwood discs & calipers (f & r)

WHEELS & TYRES
Rims: Mickey Thompson billets; 18x4 (f), 20x16 (r)
Rubber: Mickey Thompson 165 (f), Mickey Thompson Sportsman 31x18.5x20 (r)