FAMILY VALUES

MARK THOMSON BUILT HIS FAT HG PREMIER AS A COOL CRUISER, BUT IT DIDN’T GET HIS FAMILY’S TICK OF APPROVAL UNTIL IT HAD A TURBO SIX-LITRE LS V8

STORY IAIN KELLY PHOTOS CHRIS THOROGOOD

MANY of us love to involve our friends and family in our hobby, to show them why we spend all those nights with skinned knuckles working on a car we curse ’til the early hours of the morning. Fortunately for Geelong’s Mark Thomson, his wife Jodie and sons Archie and Cohen love his tough turbocharged and injected HG Premier. “It means a lot to have my wife and two sons support my hobby,” Mark says.

In fact, the reason he purchased this HG was to have a car the whole family could enjoy. “I bought it back in 2010 after completing a full resto on an HT Monaro,” he says. “I was after another project, but with kids on the scene now I wanted a four-door. I saw an 80-year-old man drive the Premier into a caryard in Footscray; I followed him in and watched him trade it in on a Holden Astra, so I bought it off the caryard.”

While it had obviously been a loved car, that didn’t mean it wasn’t in need of a fair bit of fixing, which is where Mark’s mates stepped in. Together they built a fairly traditional Geelong cruiser, complete with mini-tubs and a gruff 400ci Chev smallblock.

“The original plan was to leave it a six-cylinder for a while and just cruise around, but as the old story goes, next minute it was all pulled apart, panels sand-blasted and body paintstripped,” Mark laughs. “Rod Drew hand-fabricated all the rust repair sections; he is an incredible self-taught metal fabricator and some of the sections he made looked like they were genuine Holden parts. After the rust was sorted my good mate Mark Drew performed his magic massaging the body back into shape and also got those 295/50 tyres squeezed under the rear.”

There was no way the original Premier wheelhouses would accommodate nearly 300mm of tyre on each side, so offset shackle-mounts were fabricated and installed, shifting the reset leaf springs inward by one inch while the wheel tubs were extended to meet the inside face of each chassis rail. Once the fab work was done, Mark sent the shell off to get squirted.

“Matt Petrovics from Pro Addict Paint rubbed and prepped the car for paint and Jake Forder was good enough to let us use his booth,” Mark says. “The roof was painted in factory Kashmir White and the body in Electra Blue. Matt did an amazing job; I’m so happy with how flat the paint is on this car.

“I spent a Christmas break re-assembling the car and had it ready from paint in December to driving in January, where it debuted at the Colac Hot Rod Show.

“Now, we originally built a 400-cube Chev small-block for the HG and we drove this around for a year or so, but it was a fuelguzzler and not very inspiring. Mark Drew suggested we have a go at building a turbo LS set-up, as he had a lot of success with his wife Raelene’s HR.”

Mark and Raelene’s LQ9-powered HR has graced the pages of SM (Sep ’15), but the force-fed LS package Mark put together for his mate’s HG Premier is much tamer than Raelene’s eight-second terror. A Gen IV six-litre L98 was the base for the build, as the deep-breathing rectangle-port heads can swallow bulk air, and they’ve proven more than capable of making plenty of horsepower with basic supporting mods.

Mahle pistons and a 222/232 cam are the major improvements inside the motor, which is topped by a custom intake plenum. The turbo is a 73mm eBay special, pushing charge air through a custom air-to-air intercooler mounted between the grille and radiator.

I SAW AN 80-YEAR-OLD MAN DRIVE THE PREMIER INTO A CARYARD IN FOOTSCRAY AND TRADE IT IN ON A HOLDEN ASTRA. SO I BOUGHT IT OFF THE CARYARD

I DROVE OUT TO CALDER PARK AFTER WORK AND WENT 10.84@126MPH, THEN DROVE IT HOME TO GEELONG

Fitting LS motors in HK-T-G Holdens normally requires either converting the car to a steering rack set-up, or extensively customising the oil pan. To avoid doing things twice, Mark chose the latter. “I wanted to keep the steering original, as I’d replaced everything when I originally built the car,” he says. “I bought a fancy bolt-on sump from a supplier that was super-expensive and it didn’t fit, as it was built for rack-and-pinion steering, so I sent it back and got a stock VE sump. Drewy then cut that up to make it fit around the stock crossmember.”

Three in-tank Bosch fuel pumps supply the pump gas to the deep-breathing six-litre, from the modified original tank, while the computer is a Holden PCM from a VT Series II Commodore, flash-tuned to handle boost and the bigger cam.

On the chassis dyno the Prem laid down 523hp at the wheels, which is epic for a tidy street cruiser.

“Drewy re-built the engine, fabricated the exhaust manifold, plumbed the turbo and wired the whole car,” Mark marvels.

“His development of his wife’s turbo LS HR set-up allowed him to use his experience to build me a really nice package that performs extremely well under all conditions.”

Behind the turbo Gen IV is a transbraked two-speed Powerglide with a 3500rpm converter, built by Matty DeSpirt at MDT Race Engines & Autos. Under the bum lives a Ford nine-inch built by Matt Dietrich and the team at Geelong Differential Services, equipped with all the good gear needed to handle the turbo torque, including 35-spline axles and a Truetrac centre.

Mark reckons the driveability is awesome, with the big fourdoor happy to do domestic duties but also capable of serious speed. “It gets about 350-400km per 60-litre tank of fuel, and I dropped my two boys off to day care and kinder in it one morning, then drove it to work in Melbourne. I later drove out to Calder Park after work and went 10.84@126mph, then drove it home to Geelong.”

A 10-second family-friendly streeter in the body of an almost half-century-old cruiser? LS the world, indeed!

MARK THOMSON 1970 HOLDEN HG PREMIER

Colour: Electra Blue, Kashmir White roof

GRUNT

Type: L98 Gen IV small-block Chev Pistons: Mahle forged Intake: Custom sheet-metal Intercooler: Custom air-to-air Cam: 222/232 hydraulic-roller Turbo: 73mm eBay Special

BENEATH

’Box: Two-speed Powerglide Diff: Ford 9in, 35-spline axles, Truetrac LSD Brakes: Wilwood discs (f), HQ drums (r)

ROLLING

Rims: Mickey Thompson 15x3 (f), Max Dumesny 15x10 (r) Rubber: Mickey Thompson 155/50 (f), BF Goodrich T/A 295/50 (r)

THANKS

Thanks to a few mates for their help throughout the build: Drewy; Matty P; Sando; Scotty; Greeny; Strop (Moolap Mufflers); Matty Despirt (MDT Race Engines & Autos); Luke & Graham McMahon (Barwon Tyre Centre); Brock (Sumner Motors); Dave Smith (Dave’s Classic Autos); Dale Parsons for the use of his factory; and finally Jodes, my extremely supportive and patient wife!