WhichCar
Powered by
  • WheelsWheels
  • MOTORMOTOR
  • 4X4 Australia4X4 Australia
  • Street MachineStreet Machine
  • Trade Unique CarsTrade Unique Cars

LS3-swapped 1974 Holden HQ ute

By Tas McMillan, 15 Jan 2021 Features

Matt Watts' LS3-powered HQ ute

Matt Watts needed a ute to haul firewood, so of course he built a super-sanitary streeter with blown LS power!

WITH its stark black-on-white presentation, reverse cowl and tough big-’n’-littles stance, you can bet Matt Watts’s HQ ute snaps a few necks in this sad, beige world where car-buying decisions are often based on the number of nifty storage compartments. Matt originally set out to build something to carry a load of firewood and maybe chuck the swag in for an impromptu weekend trip, so cargo space was certainly near the top of the feature list when he went shopping for a new project car. He certainly didn’t intend to build the tyre-frying streeter the HQ is now.

This article was first published in the December 2020 issue of Street Machine. Photos: Chris Thorogood

Holden HQ Sandman ute replica rear

“I was looking for a stock-ish HQ or HZ ute,” Matt says. “My only real requirements were a bench seat and a reasonably solid body; I wasn’t fussed about the driveline.”

After finding nothing but old colanders for sale, Matt dropped in on his mate Ryan Hughes with a box of frothies under one arm and a view to relieving him of his near-mint and completely stock three-on-the-tree HQ. However, the conversation took an interesting turn when Ryan offered Matt his freshly painted white ute instead, albeit without its 408ci stroker LS and Turbo 400 powertrain. A deal was struck, and a few months later the roller was sitting in Matt’s shed.

Read next: Blown LS1-powered 1977 Holden HZ Sandman ute

Holden HQ Sandman ute replica side

The Quey’s underpinnings are mostly rebuilt standard stuff, though there are a few upgrades kicking around under there. The back end is held up by Pedders reset leaves, and Calvert double-adjustable shocks and CalTracs do their best to keep the tyres stuck to the asphalt when Matt leans on the go-pedal

“I’m a massive fan of chrome on old cars,” says Matt, “so I was going to toss all the black trims and bumpers, but when I put the wheels and HQ Sandman stripes on it I fell in love with the black-and-white combo.” Rolling on Billet Specialties Comp 5 rims on the pointy end and Max Dumesny centres mated to Weld hoops to hold up the bum, the ute now looked clean and mean. But Matt found himself second-guessing his choice of propulsion.

“My plan was to just slap an engine, gearbox and diff centre in it and get it on the road,” he says. “But the ute looked so nice that I thought it deserved something a bit more next-level under the bonnet.”

Read next: Turbo Barra-powered HZ Sandman ute - SANDBARRA

Holden HQ Sandman ute replica front

Matt had almost finished a tickled LS1 for the HQ when a fettled LSA blower set-up cropped up for sale, and then in a moment of serendipity a mate called and mentioned he had a good LS3 bottom end that he wanted to move on. Soon Matt had combined the two with a pile of choice goodies from his extensive speed parts collection to create a fitting engine for such a mean machine.

Matt added a Melling oil pump, a decent Crow cam and LS7 lifters to the stocko 6.2-litre and gave the ring gaps a boost-friendly touch-up while he was in there. The heads are untouched GM square-ports with nothing but a set of Crow double springs to help keep the combustion pressure inside the cylinders, while Castlemaine Rod Shop supplied a set of 17/8-inch four-into-ones and a sump to hold a few litres of the slippery stuff.

Holden HQ Sandman ute replica tray

The party piece bolted on top is a standard LSA blower with 1000cc injectors, lid spacer, 102mm throttlebody and a Powerbond 28 per cent-overdrive crank pulley. A Commodore LS1 ECU is the brains of the operation, and the spark is provided by GM coils that have been relocated to underneath the dashboard.

Matt handed the HQ over to Andy from Rynx Customs in Geelong to tackle the wiring and plumbing, with the brief that it all had to be well hidden. The team at Rynx did a fantastic job, so much so that Matt’s been asked by people checking out the engine bay whether the ute even runs! Somewhere in there is not only the plumbing for the fuel system but also the hoses that connect the LSA intercooler to the heat exchanger behind the grille. The ute tub houses the fuel cell and tank for the intercooler, with the battery, trans cooler and Bosch intercooler water pump hidden beneath the floor.

Holden HQ Sandman ute replica engine bay

Part of the ute’s appeal as a tough street car is that it makes plenty of power but never gets hot. The big aluminium radiator, twin thermo fans and intercooler heat exchanger are all eBay specials – all part of Matt’s cunning plan: “I tried to build it as cheap as I could, but to a reasonable level”

With the fluids out of harm’s way, there’s room underneath the ute for a twin three-inch exhaust system with MagnaFlow mufflers. “To me, LS motors sound pretty ordinary,” Matt opines. “But I’m very happy with this combo; it sounds more like a real V8!”

When the time came to turn up the wick, the HQ was delivered to Mark at Sass Automotive so he could work his magic. Unfortunately, the reconditioned TH400 that Matt had thought would do the job decided to puke its guts all over the dyno cell, so it was replaced with a Paul Rogers-built unit and a much more appropriate TCE converter. The lockdown in Victoria has prevented Mark from revisiting the tune, but with around 536hp at the bags on very safe timing and a measly 6200rpm limiter, the HQ is already a handful.

Holden HQ Sandman ute replica engine bay

The ute turned out far better than Matt intended, but it seems that the quality of the finished product may be a double-edged sword: “My dogs don’t like how loud it is, and it’s not really the most practical ute to carry firewood or dirt bikes in,” he laughs. “It won’t stop me from using it, but I still wish I’d bought the stock one!”

Holden HQ Sandman ute replica interior

There’s nothing really fancy about the cabin – it’s basically stock but with an HJ GTS dash, a few extra clocks so Matt can keep an eye on the vitals and the B&M Stealth Pro Stick for grabbing gears. “The bench seat was a must-have,” he says

MAXIMUM WATTAGE

MATT’S no stranger to Street Machine, with his blown Holden 202-powered LJ Torana, BLO202, a mainstay of the burnout scene for some years now. But there’s plenty going on in the Watts shed.

“I’m doing a pro street-style LX hatchback with an LSA, and we’re building an HG Kingswood wagon for my partner,” he says. “It’s just about back from getting painted at Gambier Kustom Autos. It’s got full custom trim, a 186 and column-shift Trimatic. It’s going to be the perfect cruiser.”

Matt Watts

Then, of course, there’s BLO UP, the KE30 Corolla that Matt threw together with a tunnel-rammed LS to take a bit of the load off the LJ. For a bloke who doesn’t like LS engines, he’s sure got a lot of them!

“I always hung shit on my mates with LS swaps because everyone does them, but bang for buck, you’d be mad not to!” he laughs.

MATT WATTS
1974 HQ HOLDEN UTE

Paint: Heron White

ENGINE
Block: GM LS3
Capacity: 6.2L
ECU: Commodore LS1
Induction: LSA supercharger
Manifold: GM
Heads: GM square-port
Camshaft: Crow
Springs: Crow double
Rockers: Stock
Pistons: Stock
Conrods: Stock
Crank: Stock
Sump: Castlemaine Rod Shop
Exhaust: Rod Shop headers, twin 3in system, MagnaFlow mufflers
Ignition: Stock coils
Cooling: Aluminium radiator, twin thermo fans

TRANSMISSION
Gearbox: Full-manual T400
Converter: TCE 3500rpm
Diff: 9in, Strange centre, billet 31-spline axles, 3.5:1 Richmond gears

SUSPENSION & BRAKES
Front: Pedders springs & shocks
Rear: Reset leaves, Calvert shocks, CalTracs
Brakes: HQ discs (f), HQ drums (r)

WHEELS & TYRES
Rims: Billet Specialties Comp 5 15x3.5 (f), custom Weld hoops with Max Dumesny centres 15x8 (r)
Rubber: Nankang 145/80R15 (f), BFGoodrich 275/50R15 (r)

THANKS
My partner Jess for her support and putting up with the long hours in the shed; Ryan Hughes; Andrew and the team at Rynx Customs; Mark Sass; Clayton Barbara; Castlemaine Rod Shop; Paul Rogers Performance Transmissions