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Blown small-block Holden HK Monaro

By Boris Viskovic | Photos: Brad Miskiewicz, 11 Feb 2019 Features

Blown small-block Holden HK Monaro

Rob Cinanni's Holden HK Monaro gets a real workout from a blown small-block sending around 800 horses to the rear wheels

This article on Rob's HK Monaro first appeared in the January 2019 issue of Street Machine

I FIRST spied Rob Cinanni’s HK Monaro back in early 2016. It was parked amongst around 600 other cars at the start point of Big Al’s Poker Run, of which there would have been at least a dozen other HK-T-G Monaros on show. I’m not sure what made it stand out from all the others; it could be that I’m a sucker for Warwick Yellow HK Monaros, or the fact it sat just right on (at the time) Weld Racing rims, or maybe it was the way the injector hat just stuck out above the bonnet. Most guys running blown motors want the whole world to know and do their utmost to get as much of it as possible out in the sunshine, but Rob took a different, stealthier path. Back then, the hat was polished, but it has since been given a black finish to make it even more low-key.

Holden HK MonaroBut let’s backtrack a little to just a couple years before I laid eyes on the HK, when Rob bought it as a stalled project from Adelaide.

“When I bought the car it was basically a bare shell – no glass, the guards and bonnet weren’t even on it, just the body, doors and bootlid,” Rob says. “It was already mini-tubbed and the glass and interior were included, but it was all just thrown in the car. It had a small-block 400 Chev in it and ran 11.0 before I got it, had the timeslips and all, so it went all right.”

Watch next: Eight-second HK Monaro owns the dyno and Tuff Street at Summernats 32

Holden HK Monaro sideThe Adelaide hubcaps measure up at 15x6 and 15x10. The mini-tubs easily swallow up the 255s that are on there for street duty, but Rob’s got plans to stuff some 305s under there

Most people would probably be happy with that, but as Rob’s already got an HQ Monaro coupe in the shed that was running 10.50s 18 years ago naturally aspirated, he knew he had to step it up a bit. The motor is still around the 400-cube mark, but it’s based around a Dart Little M block that’s been built to take the punishment an 8/71 blower can dish out using a Callies Magnum crank with a big-block snout and double keyways. There’s a set of Carrillo rods, and the JE pistons squeeze the E85 with an 8:1 ratio.

Read next: Restomod 434-cube Holden HK Monaro GTS

Holden HK MonaroWe all know that none of that is worth a damn if the heads aren’t up to the task, but Rob definitely didn’t skimp in that area. A set of AFR 245 NPP (no pushrod pinch) heads are fitted with Crower stainless shaft rockers and Manton pushrods. The cam is a custom solid-roller grind from Moose at Ranch Automotive Engineers, who also did all the machining work on the engine as well as some other choice modifications.

Read next: Rescued LS2-powered 1970 Holden HG Monaro

Holden HK Monaro onroadYou can really tell how tucked down the blower looks. It might not sound like much, but a couple of inches makes a big difference

“The manifold that came with the blower kit was really nice, but it was another 45-50mm higher than what’s on there now,” Rob explains. “I had to get another manifold – the lowest-profile one you get on the market – and then Moose welded it up to match the ports on the heads. It was a bit of stuffing around, but it was worth it because all you can see is the very top of the pulley and the hat. If you didn’t have a mate with a machine shop that could weld and machine it, you wouldn’t do that shit.”

Holden HK Monaro bootTo make lots of power you need lots of fuel, so there’s an Aeromotive Eliminator in-tank pump. The vacuum pump and reservoir are tucked to the side

Rob’s a mechanic by trade, so he screwed everything together, but he reckons that’s the easy part.

“Where the work goes in is the machining, really, so Moose should take the credit. He’s so meticulous, it’s a pain in the arse!”

Holden HK Monaro bootSitting pretty on top of the stout small-block is an 8/71 with a billet case and rotors from The Blower Shop that is topped with an Enderle bug catcher. To my eye, these are the sexiest injector hat; they just look the business and suit the era of the car to perfection.

While it might look all old-school, there’s a bit of technology hidden away, with an EFI system controlled by a BigStuff3 ECU, which took a little bit of work to get right.

Holden HK Monaro engine bayIt’s neat as a pin in the engine bay. Body colour wins out over restorer’s satin black on the guards and firewall, but the engine makes up for it with black details

“They sent me a map, but it was just enough to fire it up, it wouldn’t do anything else,” Rob says. “My mate Trevor Morrison from Mad Max Racing and I got it going. We put it on a dyno but it wouldn’t rev up over 6400rpm. Still made 765hp at the wheels, so it’s definitely going to go up around the 850 mark when we turn it to 7500. The ignition box failed on me in the end, so at least now we know what the problem was.”

Holden HK Monaro engine bayWith that much grunt, the rest of the driveline needed to be equally strong, so Rob went straight to the US and got a fully manualised, reverse-pattern Turbo 400 from Abruzzi Racing. The car was already fitted with a nine-inch, but that’s been upgraded to 35-spline, fitted with a Moser Wavetrac LSD and converted to disc brakes.

Holden HK Monaro engine bayThe mechanicals were easy for Rob, but getting the bodywork and trim sorted meant calling in some more mates to help out.

The bodywork was already about 85 per cent done, but you know how it is; that last 15 per cent is where all the hard work happens. Thanks to his good mate Marco, the old body and new panels got massaged into perfect shape before the stunning Warwick Yellow paint went on.

Holden HK Monaro engine bay“If you saw where it got painted, you’d freak out,” Rob laughs. “Actually, the whole car got built there. We had all intentions of taking it to a panel shop to paint the final colour, but we got a fine day, and with acrylic you can play with it. It was basically built from go to whoa in a lean-to!

“It took me two years; I just went flat-out on it. I didn’t walk away from it, like you do with projects. I was on it every night.”

Holden HK Monaro interiorThe interior is pretty much how it looked in 1968 except for a few extra gauges and a flash shifter

The finishing touch was to restore the interior back to factory stock, and for that Rob called in Tony Riggio. It’s been done in your basic black and only deviates from stock with the addition of a trio of AutoMeter gauges and a TCI Outlaw shifter. HK Monaro fans may notice that the iconic console-mounted tacho is missing, but don’t worry, Rob’s got the shift points covered: “There is a shift light where the choke used to be. I don’t really have time to look at a tacho; the light comes on pretty quick!”

Holden HK Monaro interiorIt’s a neat solution and it goes with Rob’s whole philosophy on the build.

“It’s not overly customised; it’s really just got a drivetrain in it,” he says. “Don’t stuff with a good thing to start with. They age beautifully, that’s all they do.”

Holden HK Monaro onroadROB CINANNI
HOLDEN HK MONARO

Paint: Warwick Yellow

ENGINE
Type: Dart Little M 403ci
Inlet: Custom
Injection: Enderle bug catcher EFI
Blower: The Blower Shop 8/71
ECU: BigStuff3
Heads: AFR 245 NPP
Valves: 2.125in (in), 1.600in (ex)
Cam: Solid-roller
Pistons: JE
Crank: Callies Magnum, big-block snout, double keyway
Conrods: Carrillo
Radiator: Aluminium
Exhaust: 17/8in headers, twin 3in system
Ignition: MSD Digital-7

SHIFT
Box: Abruzzi Racing Turbo 400
Converter: Abruzzi Racing
Diff: 9in, 35-spline, Wavetrac LSD

BENEATH
Springs: Lovells (f), leaf (r)
Shocks: Koni (f & r)
Steering: Standard
Brakes: VS Commodore (f), BA Falcon (r)

ROLLING STOCK
Rims: Center Line Auto Drag; 15x6 (f), 15x10 (r)
Rubber: 195/65/15 (f), 255/60R15 (r)