With its fire-breathing, 937hp, 598ci Jon Kaase big-block wedged between its shock towers, retina-searing paint and massive rear meats, Simon Madigan’s Yellow Glow XY practically set the pages of Street Machine alight when we featured it in the February 2014 issue. The weapons-grade Falcon also wowed punters at Meguiar’s MotorEx, the Extreme Auto Expo in Adelaide, and the Sydney Hot Rod & Custom Auto Expo, among other top shows.

First published in the September 2025 issue of Street Machine

When building that XY, Simon was already very well versed on the go side of things, having been around the Aussie and US drag racing scene since the age of eight. However, he credits his good mate Chad Venables with schooling him on the show part of the equation, and considers him the driving force behind the car’s microscopic level of detail. Unfortunately, Chad never got to see the XY fully finished, as a tragic traffic accident cut his life far too short.

As well as helping Simon with his XY, Chad had been building an XA hardtop as a drag car, aiming for eights, and that’s the car you see here. “Once I’d finished the XY, I decided to get hold of Chad’s coupe and build it as a tribute to him,” Simon explains.

When Simon eventually persuaded Chad’s fiancée to sell him the hardtop in 2012, he already had a plan in mind: “I thought to myself, ‘Why aim for eights when I could run fives?’”

The only problem was, the XA’s existing rollcage was not up to ANDRA spec to run into the five-second zone. So, out came the angle grinder, out came the ’cage, and off went the Falcon to Henley Chassis for a twin-rail, full chrome-moly replacement that would be compliant to run to the new 5.80 index in Supercharged Outlaws.

While the hardtop’s turret and quarters are still steel, everything else is fibreglass. That said, Simon was still adamant that the body lines and door gaps of the mostly ’glass panels had to be spot-on, and body man Scott Lang was more than up to the task. Scott modified every single panel, which included sharpening up the style lines and raking the nose down 100mm from the windscreen without making it look ‘wrong’. Rather than the one-piece, lift-off front end you’d typically find on a race car, PRO GT’s bonnet can be removed separately, yet the whole front section weighs a scant 20kg!

With the XA’s body mods finalised and the panelwork arrow straight, it was time for paint maestro Darren Smith to work his magic. Again, Simon was a tough taskmaster, insisting the finish on the chassis and rollcage be just as good as the exterior panels. Anybody who’s ever tried painting a ’cage will know what a tough order that is, but as you can see, Darren revelled in the challenge, ensuring every square inch of the Falcon’s innards were as show quality as the outside.

As with any serious race car, PRO GT required a full custom wiring harness and electrical system, which was sorted by Danny at DesignWire. “I’ve never seen wiring quite like this,” says Simon. “The looms, the programming of the electrical systems; his work is the best in the business.”

While all this was going on, Simon busied himself with tracking down an engine capable of pushing the hardtop to that 5.80-second Supercharged Outlaws cut-off. “Most racers take the easy route and use a Hemi or something like a Pro Line 481X,” he says. “Not me; I’m pretty stupid – for me, it has to be a Ford-in-a-Ford. Benny Gatt is about the only other guy I know that runs a Ford in Outlaws.”

Simon’s search netted him a complete 632-cube, all-alloy big-block Ford. It features a Bryant crank, Moran alloy rods, cavernous C460 heads, titanium valves, and a Barnes five-stage dry sump, among many other goodies. A custom sheet-metal intake was fabricated to support the gargantuan SSi high-helix 14/71 blower and towering Enderle Big & Ugly hat. The finishing touch is the insane four-into-one stepped headers by Damon at Airs Race Pipes, with 2.5-inch primaries dumping into a five-inch collector.

Unfortunately, on the engine’s first fire-up, it was obvious all not was right, so the mill was sent to engine guru Jason Maros, who built V8 Supercar donks for Larry Perkins for many years. Disassembly revealed a number of issues, so while Jason was correcting those, Simon brought in Dandy Engines’ Frank Marchese and Nathaniel Ardern of FuelTech Australia to convert the 3000hp big-block from traditional magneto and mechanical injection to full electronic control.

The methanol-slurping 632 now runs 16 injectors and an ignition system controlled by a FuelTech ECU. Simon also opted to include a comprehensive suite of sensors. “It’s got more bells and whistles than the space shuttle,” he laughs. “In fact, Nathaniel and Frank can log in remotely to update the tune from their lounge room.”

To date, PRO GT has been a 12-year labour of love, both for Simon and his wife Rachel. “Rachel understood how committed I was,” says Simon. “She has done a hell of a lot of hard yards on the car. I would never have been able to finish it without her time, commitment and endless support.”

While it wasn’t yet running, Rachel and Simon did have the Falcon finished enough to display at Adelaide’s Extreme Auto Expo for the 10th anniversary of Chad’s passing. Now, with the engine gremlins sorted and the car 100 per cent finished, and all that’s left to do is some testing before heading to the Spring Nationals at The Bend in October. At the time of writing, with all going well, that’s where PRO GT will pick up that long-awaited five-second timeslip.

BRIGHT YELLOW

As far as Simon’s concerned, he has his good mate, the late Chad Venables, to thank for the incredible level of detail packed into his previous build, this eye-popping XY (pictured below, SM, Feb ’14). The truckload of trophies the car won at the 2013 Extreme Auto Expo, including Best Street Machine, Best Paint and Best Sedan, certainly attest to that.

Highlights included a 598ci, P-51-headed big-block Ford screwed together by legendary US builder Jon Kaase, which spat out 937hp. There were also tubs, a four-link and a braced 9in out back, ProStrut coil-overs up front, and a full-manual C6 trans in between, while the cabin featured a classy GT-style interior.

SIMON MADIGAN
1973 FORD XA FALCON GT HARDTOP

THANKS
Darren Smith at DRT Restorations; Scott Lang; Jason at Maros Race Engines; Brett Henley of Henley Chassis; Damon Air at Airs Race Pipes; Dimmy at Autopro Kilkenny; the team at Check it Out Graphics; Frank Marchese; Nathaniel Ardern at FuelTech; all my friends who helped along the way, including Andrew, Frank, Rob, Mick, Darryl, Ray – the list goes on; my wife Rachel for all her help and encouragement to stick with it.