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LS1-powered 1971 Ford Falcon XY GT replica

By Curt Dupriez, 05 Mar 2021 Features

LS1-powered 1971 Ford Falcon XY GT replica

Blue Oval fans better brace themselves for what's under the bonnet

WITH classic electric-blue paint and Weld 15-inch runners, you’d swear that Willem Fercher’s XY GT replica is a roof-to-rubber tribute to Ford’s rich local muscle car bloodline. But the silver GT 350 stripes make you wonder if his Clevo’s an inch short.

First published in the March 2007 issue of Street Machine. Photos: Phil Cooper

He turns the key and eight slugs kick into life. But it’s buttery smooth. When he pops the bonnet everything looks in order. 

Ford Falcon XY rear

But why is there an alloy shroud over the dizzy? And four coil packs on each cylinder head? Any blue oval nut knows this ain’t a Ford donk. Nope, it’s a Chev engine — an LS1 Gen III in a Hoey!

Henry must be spinning in his grave like a Clevo on redline. Street machiners love to break rules but few dare to break The Unspoken Rule. So the big question is why?

Read next: LS1-powered XW Fairmont GS

Ford Falcon XY

“It came down to money,” Willem says. The full explanation is little more long-winded.

“A carbie 351 is too heavy on the front end and the alloy Ford Motorsport gear is too pricey. I built the XY when BA was only just released, so forget about sourcing a BOSS 290 V8 cheaply. Bar the turbo six, Ford hasn’t got an engine that’ll provide the Chev’s bang for the bucks. The Chev will do 400 horses for just five grand.”

If he were starting the project today, he’d lean towards a BOSS 290 but Willem defends the Gen III’s benefits.

Ford Falcon XY under

“I’m a circuit racer and I track sprint this XY. The Chev is as light as a six and bulletproof at the level of power it’s making. I also have a family of four and the Chev is far more economical for cruising than a carbie 351 — although it sucks as much juice as a Clevo when you put the foot down.”

That’s all logical stuff but the clincher was when Willem, a mechanic who runs Winmalee Car Care west of Sydney, whipped out the tape measure.

Read next: Blown LS1-powered 1971 XY Falcon 500 drifter - XYNOT

“It’s almost as if the Gen III was designed for the XY engine bay,” he claims. It fits like a glove, no firewall mods. But the real surprise is that the Gen III’s sump and the XY front crossmember are unmodified. That’d make early Holden owners who want LS1 conversions turn green with envy. “Even the engine mounting points line up,” he adds.

Ford Falcon GT-350

Keen eyes will notice the notch job in the strut towers for header clearance, an off-the-shelf RRS template and brace kit intended for big-block and turbo V8 conversions.

Read next: LS engine variants part one - Gen III

“It’s awesome,” Willem says, “you just cut the towers using the templates, then weld in the supplied metal and braces. I had no problems with certification.”

For the XY’s Jekyll and Hyde mix of cruising and circuit work, the Chev’s copped little more than a tickle — a Competition Cams bumpstick, ECU tweak, and up-rated EFI-friendly fuel system using bigger 380cc injectors, a custom fuel cell and Bosch Motorsport/Malpassi delivery system.

Ford Falcon XY brakes

“If it breaks I’ll just slot in another Gen III,” he says.

Getting the Commodore T56 six-speed manual to fit a tunnel designed for a ’box with half the cogs required some creative tunnelling but feeding grunt to the bags was easy: a custom tail-shaft to suit the 4.11:1 nine-inch diff.

Read next: Blown LS-powered Ford Falcon XD

“The only dramas I’ve had on track have been with the last piece of Ford gear left in the driveline, the diff. It’s let me down twice — just diff pressure that makes it spew oil under track conditions.”

Ford Falcon XY engine bay

With all this track talk, it’s no surprise that the handling and brakes have been re-engineered. A pair of RRS’s adjustable coil-over MacPherson struts grace the front end (see side bar), while the rear is traditional XY with top-shelf King Springs and Koni dampers. Willem also sharpened the steering with an XF power-steer conversion.

“I can dial-up good front-end negative-camber now and the thing really points and steers,” he says.

Brakes are the latest alloy twin-piston PBR calipers.

Ford Falcon XY engine bay

“It’s not easy to find ventilated rear rotors. Almost everyone offers solid discs, so it uses XC rotors up the back. The brakes are as big as I could I fit under the Weld wheels. They never fade on track but I can still keep that old-school look with the 15-inch rims.”

The system’s also equipped with a race-style front/rear bias adjuster.

“It’s awesome to drive. It cruises at 110km/h in sixth gear effortlessly. The other week on the track, it had more mid-corner speed than a couple of AUs. It ran 12.9@110mph first time down the quarter, on street tyres.”

A far cry from the grandpa-spec six Willem bought.

Ford Falcon XY

“It had 96,000 miles on the clock, with original paint and excellent metal,” Willem says. But it was poo-brown. A bloke named Neil Feltus performed the strip and prep prior to Katoomba’s The Repair Wizard laying on the Glazurit Electric Blue two-pack. After Willem sourced repro GT gear, restored the old trim parts and installed new glass, the custom-made GT 350 stripes were laid on by Glen Brasington.

“Most of the gear is new. Finding parts wasn’t too tough; I got a lot out of Qld and some from Vic.”

Willem also changed the interior from brown to black. “Bar some driver’s seat sag, the old trim was in near-new condition.

Ford Falcon XY driving

But we had to change everything.” It’s convincing too — even the T56 shifter looks original.

“When hardcore Ford blokes see the engine it puts them off but the interior sways them back. I’ve had heaps of good comments about the Auto Meter gauges in the factory locations. And I haven’t had any punch-ups yet.”

WILLEM FERCHER
1971 FORD XY FALCON GT REPLICA

Colour: Glazurit Electric Blue two-pack

DONK
Engine: Gen III V8
Cam: Competition Cams, 0.574lift/110deg
Fuel: EFI conversion, custom 19-litre fuel cell with lift pump
Exhaust: Custom headers, dual 2.5-inch system

DRIVE
Gearbox: T56 six-speed manual, Textralia button clutch, light billet flywheel
Diff: Ford nine-inch with LSD, 4.11:1 gears, custom three-inch tailshaft
Brakes: PBR two-pot calipers, ventilated and slotted 300mm discs (f), single-pot calipers, XC Falcon 297mm discs (r), Strange bias adjuster

DRIVEN
Seats: Originals re-trimmed to XY GT spec in black vinyl
Wheel: MOMO
Gauges: Auto Meter

DUMPED
Suspension: RSS coil-over strut (f), stock (r)
Springs/shocks: Eibach/Koni adjustable coil-over (f), King Springs, Koni shocks (r), Noltec bushes, sway bars
Wheels: Weld 15x8 (f), 15x8 (r)
Tyres: 215/60 (f), 245/60 (r)

SPECIAL THANKS
The Fercher family, the lads at Winmalee Car Care, Windsor Exhaust Centre, Blaxland Auto Electrics, The Repair Wizard, Neil Feltus