BRENDAN CHERRY'S TWIN-TURBO 1968 HOLDEN HK MONARO

holden hk monaro 4 nw

Brendan Cherry breaks out some flash new moves with his show-worthy, big-grunt twin-turbo HK and gets set for SM Drag Challenge

This story on Brendan's HK Monaro was originally published in the September 2017 issue of Street Machine

THEY say that change is as good as a holiday, although I’m sure many would happily embrace the status quo if it meant owning an eight-second HQ coupe. But if the passion for a certain build has run its course or there’s the burning feeling of unfinished business, maybe it is time to change things up.

Street Machine Drag Challenge stalwart and burnout enthusiast Brendan Cherry was at these exact crossroads earlier this year. “My AGRO-01 HQ Monaro was in a great place with its twin-turbo 408-cube LS combo and a heap of cruising and racing under its belt, but I was starting to get a little bored,” he explains. “My ultimate car has long been an HK Monaro, but owning one just plain eluded me. If the right car popped up I couldn’t afford it, or if I had some cash to throw around there was nothing decent on offer.”

Twin-turbo LS Holden HK Monaro GTS

Holden HK Monaro profileSo one evening Brendan decided to post a wanted ad for an HK on Facebook, just to casually see what may have been up for grabs. Next minute he’d laid down a healthy deposit on this show ’n’ go Monaro from Queensland dubbed SIRHK, and his HQ was on the market.

“It all happened so fast,” he says. “When the original owner, Scott Bliss, sent me photos of the car I couldn’t say no. I bought it sight unseen and immediately advertised the HQ; that sold within 18 hours of listing it!”

Pro Touring LSX-powered Holden HT Monaro

Holden HK Monaro rearNo stranger to ground-up rebuilds, Brendan chose a different path this time around, buying the HK as a finished build. “I know this car has been done right. There are so many little things I’ve spotted like custom CNCed washers under the bolts,” he says. “There’s still plenty to do before this year’s Drag Challenge but the biggest hurdle has been a lack of track time

The now-candy green HQ found its way to a new home – minus his trademark AGRO-01 plates of course – and Brendan readied himself for the arrival of his new ride. “The two-week wait was a killer,” he says. “It was a fresh car on the scene and built in Mackay; Scott had shown it at MotorEx in Sydney, but that was it. I knew it was a quality thing, but the finish in the flesh knocked me for six; you just know it’s been done right. It is probably a bit too nice for me and how I treat cars though!”

So with the HK safely nestled at Brendan’s digs, he hatched a plan to ready the car for this year’s Drag Challenge. The Monaro was already big block-powered and sporting EFI, which cleared two large hurdles, and had been properly ‘caged and tubbed – the latter to house a set of fat FR18 Simmons rims.

Holden HK Monaro bonnet upVisually the Monaro remains as-purchased save for a set of drag-friendly Weld V-Series rims that replaced big-inch Simmons FR18s. The shape-shifting Black Gold hue has been lavished over a near-stock exterior, save for a reverse-cowl bonnet (now changed to a fibreglass item), HQ door handles and the shaving of all badgework

“The wheels were the first thing to go, because it needed to be drag-spec, not the show look,” Brendan says. “That, along with a change to the ride height, meant a reset of the pinion angles, which wasn’t easy since the transmission tunnel had to be modified to suit.

“I want the car to run eights on a small tyre, so next on the agenda was to step up the ‘go’ side,” he continues. “I did race it as-bought, and laid down an N/A 11-flat at 127mph, so it had some grunt to match its showy looks. Mind you, that was with a shitload of wheelspin and a dismal 2.2-second 60-foot time! I was rapt when I changed from a single turbo to twins with the HQ, so decided on the same set-up for this one.”

Holden HK Monaro bonnet scoopThe car was sent to Stroke Me Racing Fabrication to have the twin-turbo installation sorted, which involved the fitment of a pair of BorgWarner S480 80mm units matched to Turbosmart wastegates, along with a custom intercooler plumbed via custom stainless pipes.

The process of fitting a heavy-breathing combo like this and actually making it pump out reliable neddies was made significantly easier due to the engine already in the HK being no shrinking violet. Under Scott’s tutelage, the Monaro was specced with a nitrous-ready 572-cube Merlin big-block Chev, running a Callies crank and Oliver conrods, while Merlin 3.0 alloy heads were topped with an Edelbrock intake and a Holley throttlebody.

Holden HK Monaro wheelBrendan’s horsepower needs were sorted at Kanaris Engines with a cam change and fitment of ID 2200 injectors, and the existing FAST XFI ECU was reprogrammed to suit.

An E85 diet is fed via a trio of Walbro 460S fuel pumps, with the resulting exhaust whisked away through a custom twin 3.5-inch system. A hefty aluminium radiator was chosen to keep both the street and strip temps in check, and since these photos were taken, the ignition has been upgraded to a crank trigger system using a brace of LS3 coils.

Holden HK Molnaro engine bayA Merlin-based 572ci BBC was already front and centre when Brendan bought the HK, so the twin BorgWarner S480 turbo set-up and supporting plumbing and fuel system requirements were added to the existing combo. “Going from an LS in my HQ to a big-block has been a totally different ballgame,” Brendan says. “The torque and easy power this engine makes at low boost is incredible!”

A Turbo 400 transmission containing all the fruit was built by Andrew from Preston Automatics, along with a TCE 3200 converter – both necessary upgrades as Brendan and Frank from Allsparks Performance refine the significant boost in horsepower.

Holden HK Monaro engine“There have been a few teething problems, as you’d expect from a brand new build; there were only 214 miles on the clock when the HK arrived,” Brendan says. “But we are starting to see great potential with this car and have seen 1000rwhp on the dyno, with more to come with further tuning.”

Another projected change will be a switch to 3.2 gears from the current 3.5s in the sheet-metal nine-inch, and Brendan has already outfitted the rear suspension with a selection of Gazzard Brothers componentry and AFCO shocks.

Holden HK Monaro bootThe original front end features Pedders springs and 90/10-rate shock absorbers, while a Torana steering rack conversion has replaced the conventional HK recirculating ball set-up.

A mix of VE Commodore front discs and Wilwood rears are activated by a Wilwood master cylinder and housed in 17-inch front and 15-inch rear Weld V-Series rims wrapped in matching Mickey Thompson front-runners and 255/60 radial R tyres.

Holden HK Monaro interior frontThe GTS-based interior fixtures were trimmed in cream leather by Jim McGill Motor Trimmers, with the ’cage and dash frame painted to match. Brendan hopes he can keep the show-spec finish looking schmick throughout the imminent rigours of Drag Challenge and regular street use. “I think I’ll just whip up a set of seat covers that blanket the entire interior,” he laughs

Spray painter Brendan describes the Monaro’s body and paint as “mint”, and that’s not him blowing his own trumpet; it was the work of Chris Pace at Pace’s Automotive Refinishing in Mackay, who handled much of the original build. The body remains close to stock apart from deleting the fuel filler and swapping out the original handles for HQ items. The pictured reverse-cowl bonnet has since been replaced with a ’glass version that features more of the original centre pressings. “I’m happy not to have to paint the car; I’ve got enough to do as it is,” Brendan laughs. “Of course I painted the new bonnet and touched up the engine bay after the turbo conversion, but otherwise the exterior is as-bought.”

Holden HK Monaro dashThe colour is a custom mix dubbed Black Gold, which goes crazy in different light; I’m not sure whether to call it green, brown, black or gold, so I’ll let you make up your own mind.

If the engine and paint haven’t left you speechless, then swing open one of those big coupe doors and take a peek inside. Mackay’s Jim McGill Motor Trimmers stitched the gorgeous cream leather trim that surrounds factory GTS front and rear seats, with the custom sheet-metal console, chrome-moly six-point ’cage and any remaining adjacent surfaces finished to match. An HK GTS steering wheel retains the Monaro factory muscle pedigree, while a TCI shifter and Auto Meter gauges match its modern performance capabilities.

Holden HK Monaro interior rear“My immediate goals for the HK are to complete this year’s Drag Challenge, land a spot in the Summernats Top 60 and get it to run mid-eights like my old HQ,” Brendan declares. “There’s still a lot to do before Drag Challenge, with a heap more tuning and setting up of both the boost control and traction control to help it all come together, and of course mounting a parachute and getting the car ANDRA-teched.

Holden HK Monaro glovebox“The hardest part though will be to keep it looking as good as it does now; I’m used to having stone chips and marks on my cars, but will clear-wrap the lower guards on this for Drag Challenge and hope like hell that my mates can keep their grubby mitts off it too! They’ve already nicknamed it ‘Trophy Hunter’ because of its showy finish, but it’s the racing tinware that appeals to me more.”

Holden HK Monaro onroadBRENDAN CHERRY
1968 HOLDEN HK MONARO

Colour: Black Gold

ENGINE
Engine: Chevrolet 572ci
Block: Merlin
Turbos: BorgWarner S480
Intake: Edelbrock
Throttlebody: Holley
Heads: Merlin 3.0 alloy
Crank: Callies
Rods: Oliver
Cam: Custom roller
ECU: FAST XFI 2.0
Ignition: 8 x LS3 coils, crank trigger
Exhaust: Custom 4-into-1 headers, twin 3.5in system

TRANSMISSION
Transmission: Turbo 400
Converter: TCE 3200 stall
Diff: Fabricated 9in, 3.5:1 gears

BENEATH
Front: Pedders coils, 90/10 shocks
Rear: Gazzard Bros mono-leaf, AFCO shock absorbers
Brakes: VE Commodore discs (f), Wilwood discs (r); Wilwood master cylinder

WHEELS & TYRES
Rims: Weld V-Series 17x4 (f), Weld V-Series beadlock 15x8.5 (r)
Tyres: M/T front runners (f), M/T 255/60 Radial R (r)

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