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Turbo 358-cube 1971 Holden HQ GTS coupe

By Scott Taylor | Photos: Chris Thorogood, 08 Mar 2020 Features

Turbo 358-cube 1971 Holden HQ GTS coupe

Take a Chevy V8, add a turbo and a little boost and you've got a recipe for horsepower

YEARS ago, turbocharged V8 streeters were a rarity in Australia but these days it seems everyone wants to enjoy the thrill of exhaust-driven boost. And why not? Especially when you see rides like Tom Fraser’s beautiful HQ GTS coupe pumping 600hp at the treads.

This article was first published in the September 2011 issue of Street Machine

Holden HQ GTS coupe rear

Tom’s owned the cool coupe for half his life; okay so he’s only 30 but how many of us can say we still own our first car?

“I’ve had three or four of them but this is the one I’ve kept,” he says. “I saw an ad on a milk bar window. It was on a farm out bush and I paid $3000 for it with a reco’ed 308 before I was 16, so it sat there for a little while, but as soon as I turned 16 I was driving it all the time.”

Read next: 540-cube big-block 1971 HQ Monaro GTS

Holden Monaro HQ GTS coupe

It was a hell of a ride for a young bloke too — who wouldn’t want a genuine 308-powered GTS coupe as their first ride?

“I took it to a Monaro show and the guys were all checking out the ID plate, and then looking at me, then looking at the car again. They weren’t happy that I’d tubbed it — they reckon it’s pretty rare because it was factory green with white trim. But I’m more into drags and stuff, not static shows.”

Read next: SMOTY-winning pro street big-block 1971 HQ Statesman

Holden HQ GTS coupe side

But we’re getting ahead of ourselves. Tom’s tale of pain and modification started with a trip to Easternats when he was 18.

“I blew the diff up on the way home,” he says ruefully. That’s where it all started. “First it was fix the diff, then upgrade the gearbox, and then I thought I’d put EFI heads on it and it just escalated. I think it was seven years between drives.”

Read next: Blown 1973 HQ Monaro

Holden HQ GTS coupe

During that time the coupe was tubbed, ’caged, retrimmed in white and painted in PPG Lindgruen, a Holden Barina colour. The 308 was given a healthy dose of power too, thanks to a COME twin-throttlebody EFI manifold and a Haltech ECU, while a Powerglide and healthy nine-inch made sure Tom’s diff-breaking days were a distant memory.

But 300hp at the rear wasn’t enough, especially when he saw his good mate Brad Keem punching out bigger numbers with his blow-through turbo Hemi six Charger.

Holden HQ GTS coupe boot

Magnafuel Prostar EFI 750 pump and Aeromotive 13202 regulator ensure there’s a constant stream of fuel available

“I took it to Vic Supercruz and Easternats, then sold all the EFI Holden stuff and started on the Chev set-up,” he says.

Shopping for power is often a troublesome mission and he soon learned that some things just aren’t worth the dollars.

“I bought a long motor from a guy in Sydney. It was supposed to be all good but the block was cracked and it was stuffed. The only things I used were the alloy heads and the intake manifold.”

Holden HQ GTS engine bay

The GT42 is making 5psi boost by 2700rpm, with 16psi all in before 4000rpm. The carb hat and solid roller camshaft were bought from Steve Morris Racing in the US

So he looked around and found a factory 010 block that was part-way through a splayed four-bolt conversion. It was also partially grout-filled but Tom didn’t care as he planned to run it on methanol. Trouble was, the machine shop stuffed the rest of the conversion — but the boys only discovered that later on. Not long after they tuned it, the engine snapped the locating dowel on the cam, which took out the timing chain. It was only when they pulled it down to fix that little problem that they discovered the main caps had been done poorly.

Holden HQ GTS engine bay

“Don’t take anyone’s word for anything,” is Tom’s advice now. “Check it all yourself, and don’t start with 30-year-old junk.” Wise words from someone who’s learnt the hard way.

Holden HQ GTS interior

He has now purchased a brand new Dart Little-M block to avoid such problems. It’s been an expensive lesson but it wasn’t all bad because they had a chance to dial in some of the new set-up before the timing gear called time on the old block.

At 358 cubes, the Chevy small-block made a fairly easy 603rwhp at just 16psi boost and with bugger-all timing in it. With the base timing map set in the MSD Digital 7 they’ll be able to get the new donk up and running in no time.

Holden HQ GTS seats

The Dart, this time machined by North Geelong Engine Reconditioners, has been filled with all the same good gear — Eagle crank, Scat rods and JE pistons. Up top it’s running a C&S Specialities blow-through 850cfm methanol carb, a purchase Tom’s been very happy with.

“It’s really tunable. It reacts to every jet and timing change. At the time people couldn’t believe I’d paid that much for a carby but Roger [from C&S Specialties in the US] is awesome. You can ring up and talk to him and not get told he’s too busy. It doesn’t matter what question, or how stupid it is, he’ll always answer.”

Holden HQ GTS dash

Eventually Tom hopes to go up to 25psi boost but admits he might need to go for a larger turbo — maybe a GT55 — to get the job done. And there is a job to be done; he has some quarter-mile plans.

“It was always destined to be a street and strip car,” Tom reckons. “I love that Modified Street scene and I’d love to run mid-eights in the Radial class but I’ll need to upgrade the turbo first.”

Holden HQ GTS onroad

First he has to make some tough — though enviable — decisions.

“Originally I set it up for methanol with the grout-filled block but I might set the Dart block up for E85. That probably means I’ll need to make room for an intercooler. How far do you go, though? The car is too good to cut up any further so I might build something else and put this motor in it.”

Tom Fraser

TOM FRASER
1971 HQ GTS COUPE

Colour: PPG Lindgruen

GRUNT
Engine: Chev 358ci
Carb: C&S 850cfm, methanol blow-through
Turbo: Garrett GT42
Intake: Brodix HV1
Heads: Brodix Track-1
Pistons: JE forged turbo
Crank: Eagle forged
Rods: Scat H-beam
Cam: Steve Morris solid roller
Ignition: MSD Digital 7 with boost retard, MSD crank trigger
Exhaust: Custom turbo manifolds, four-inch exhaust

SHIFT
Transmission: Powerglide, full manual, transbrake
Converter: Dominator 9½in 4000rpm
Diff: Nine-inch, billet 31-spline axles, 3.5 gears, full spool, half-inch studs

BENEATH
Brakes: DBA cross-drilled & slotted (f), HQ drum (r)
Springs: King super low (f), Pedders low (r)
Shocks: Pedders 90/10 (f), Pedders 50/50 (r)
Bushes: Nolathane

ROLLING
Rims: Center Line, Convo Pro, 15x4 (f), 15x10 (r)
Rubber: Nankang (f), M/T Drag Radials 275/60 (r)

THANKS
Brad Keem, Ryan Dew, Matt Newcomb, Dean Garner (paint), C&S Specialties (carby), Steve Morris Race Engines (carb hat & camshaft), North Geelong Engine Reconditioners, Exhaust Brothers Geelong (turbo manifolds), Repco Colac, Mum & Dad, girlfriend Teghan & daughter Rhuby, Aaron Norman, Eastern Auto Upholstery, Rix Upholstery (head lining & final install), Gauge Works Geelong, Les Dew, Andrew Sanders at Specialised Power Porting and Glenn Conway