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5.7-litre V8-powered 1980 'Pro 350' Holden Gemini - flashback

By Mark Boxer | Photos: Guy Bowden, 24 Dec 2019 Features

5.7-litre V8-powered 1980 'Pro 350' Holden Gemini - flashback

Leroy Hancox's 5.7-litre golden glory is anything but a gentleman's Gemini

YOU’VE gotta think it’s a tad weird when a big, tough-looking guy gets all excited about showing you his Holden Gemini. But when Leroy Hancox turns the ignition key to start it up, the motive for his excitement becomes apparent.

This article was first published in the March 2002 issue of Street Machine

Holden Gemini

When a neat and tidy little Gemini is fitted with 5.7 litres of Chevrolet’s bent best, creating enough noise and rumble to make the average backyard shed reverberate like crazy, you get the idea that the owner likes small cars with big engines.

Having spent a fair chunk of its life as Leroy’s wife Antonietta’s run around the Gemini was the source of constant nightmares for Leroy, all starting the morning a half-asleep garbo’s truck took out the rear quarter-panel when he wasn’t looking where he was heading.

Read next: 370ci Chev-powered Gemini burnout car - SEND IT

Holden Gemini

“Wasn’t a real prob though. I just got a whole new quarter and replaced it rather than trying to straighten the old one,” says Leroy, who runs out of fingers counting the number of cars he’s given the go-fast-and-look-cool treatment. You see, since Leroy turned 16, he’s been the proud owner of stacks of tuff cars – a two-litre Capri, several big 50s and 60s Chevs, a Datto 240Z and a Cadillac with a boot big enough to fit in two Geminis.

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Holden Gemini

Unfortunately things didn’t seem to be going the way Leroy had planned. After getting the Gemini back to its former glory, the engine decided that it wasn’t interested in the whole turning over and running bit anymore. It came to a sudden stop while Antonietta was on the way to work. No great tragedy for Leroy though, just another opportunity for him to get his hands grubby.

The motor was pulled down, given a crank grind, new bearings and was running again in no time. That was until they took it for a test drive. On came the oil light, followed by some not so great clunking noises. The oil pump wasn’t up to scratch and left the engine a little dry – kinda like having sex with sandpaper.

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Holden Gemini

Enough was enough. No more bloody Isuzu engines. If Leroy had to waste more hours over the engine bay, he was going to at least have the thing go better than a standard Gemini.

What kind of engine do you stick in a Gemini when you plan to make it go like a cut snake? A Nissan FJ20 turbo. They’re, strong, reliable and have heaps more grunt than an Isuzu G18 motor. Dropping an FJ20 into a Gemini wasn’t uncommon either, so it wasn’t going to be a nightmare conversion. It was the perfect plan: build something reliable yet quick enough to take to the drags.

Holden Gemini bonnet

With rear tyres not much wider than a bicycle, there wasn’t going to be a great deal of traction. After coming across a set of 15x10 and 15x3.5 Welds at the right price, a visit to the boys at CDS Engineering saw the car soon emerge with a set of tubs, roll cage, frame-rail connectors and Ford nine-inch.

The car was brought home to do the bodywork. It was then that Leroy’s mates Dominic and Paul hinted to him that he was maybe going a little overboard for a little four-cylinder turbo and began waving around a tape measure in order to show Leroy that a lumpy, noisy, grunty, ground-shaking V8 might be a better way to go. Leroy thought about it, then grinned having pictured himself pulling burnouts from one end of the suburb to the other.

Holden Gemini engine bay

Once a dummy set-up was done, it was full steam ahead. Since the engine bay isn’t all that long, the engine sits back in the firewall, while up front a four-core Land Rover radiator is relocated 3.5 inches further forward than standard. Also, rather than standard engine mounts, the donk sits on drag car-style plates.

Pulling up the Gemini was another issue. On the front Leroy fitted XA Falcon rotors, clamped by HQ calipers mounted on Rod Hadfield brackets, while the rear utilises standard XF Falcon drums. The lack of engine bay space has also meant that a remote VH44 brake booster is located under the right-hand guard.

Leroy opted for a set of 90/10 shocks combined with Audi coil springs up the front. The steering still all remains standard Gemini, while the new diff is mounted on reset RS2000 leaf springs.

Holden Gemini engine bay

For a splash of colour, Leroy took the car to Rob Zganec at SA crash, who gave it multiple layers, of two-pack Explosive Gelb – a colour found on a late model Fiats. Silver-coated plastic TG Gemini bumpers were used rather than the TE metal ones.

On the inside, the Gemini still retains standard seats that have been retrimmed with late model Commodore SS trim, although the rear is much skinnier due to the tubs. A B&M Pro Ratchet shifter makes the forwards-backwards decisions, while an array of Auto Meter gauges mounted behind the Terminator billet steering wheel, on the bonnet and under the dash display what’s going on up front. For drag racing necessity, a six-point cage was added, along with a pair of RPM harnesses that hold Leroy in tight. A recent addition is the custom blue anodised door trim. It replaces the previous cloth version that matched the seats, to make it a “bit more race-looking”.

Holden Gemini engine bay

Under the bonnet scoop sits a four-bolt 350 Chev bored to 355ci. KB pop-top slugs are pushed and pulled by prepped X rods strapped onto a deburred standard crank. A Crane F244 solid cam opens and shuts a set of Miloden valves, held tight in the 474hp flowed Power Pak heads by Crane double valve springs. Lubrication comes via a high volume Mellings oil pump that sucks from a custom sump and keeps the Chevlite 77 bearings all warm and gooey. On top of the Victor Jnr manifold sits a Pro Flow 850 double pumper fed by a Barry Grant fuel pump, while the Avgas is ignited by an MSD Pro Billet dizzy, triggering an MSD 6AL, that chucks lightning bolts produced by an Accel coil down 10mm Top Gun leads.

Leroy’s chosen box of gears is a Turbo 350 with heavy-duty clutches and a 4200rpm Dominator stall converter. Shifting the drive is a custom three-inch tailshaft. Recently changing to 3.89 diff gears has improved his best quarter-mile time to an 11.08 at 121mph. Not far off a 10, but while drag racing can be great fun, Leroy and Antonietta do enjoy a decent Saturday night cruise, especially between the city and Glenelg Beach along the ever popular Anzac Hwy.

Holden Gemini boot

“We have driven roughly 4000km around Adelaide, it’s great seeing the looks on people’s faces as you pass by or pull up along side them. I’ve even had a few cops give me the thumbs up,” smiles Leroy.

In the short-term future, with the assistance a new engine builder, Leroy hopes to drop his time over the quarter mile. Long term? Well, there was mention of some forced induction, maybe a pair of turbos, maybe a blower, or maybe even a whole different angle – a 20B rotary.

“Those things sound wild, kinda like formula one engines,” Leroy enthuses. If you consider what this Gemini was and how tough it is now, don’t take being hit by a garbage truck for granted.

Holden Gemini dash

Redundant Batarangs make great steering wheels

IT’S IN THE STARS

EVER read your horoscope? I found one that describes Leroy’s car perfectly: “Gemini’s are impulsive and hate hanging around. Boredom and relaxation frightens them. If they’re not on the move they go mad. If you have a Gemini friend, life will never be dull.” Friends indeed, and the list is long. Leroy would like to thank all the people that helped him get the car to its current form. His mates, Peter, George, Matt, Dominic, Scott and Paul. His sponsors and businesses that helped out are, Gower Heads, CDS Engineering, Competition Engines, Outlaw Speed Shop, Hair Biz, Bowtie Racing and Specialty Tuning. Most of all, his mum, dad, brother and wife Antoietta for letting him live his dream and helping it to come true to life. 

LEROY & ANTONIETTA HANCOX
1980 ‘PRO 350’ GEMINI

Colour: Glasruit Explosive Gelb

PRO DONK
Engine: 350 Chev bored to 355ci
Heads: Power Pak
Intake: Victor Jnr
Carby: Pro Flow 850 double pumper
Cam: Crane F244 Solid

PRO DRIVE
Transmission: Turbo 350, Dominator 4200 stall
Diff: Ford nine-inch, 3.89 gears
Suspension: Audi springs, 90/10 shocks(fr) reset RS2000 leafs(Rr)
Brakes: XA rotors, HQ calipers(fr) XF drums(Rr)

PRO TRIM
Seats: Gemini, SS Commodore trim
Wheel: Terminator billet

PRO ROLLERS
Rims: 15x10 and 15x3.5 Welds
Rubber: T/A 295/50/15 and Michellin 135x15

 

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