Barra-swapped 1966 Mustang fastback

Justin Stephenson went searching for a new rig to Barra-swap and returned from his quest with a 10-second Mustang fastback

Photographers: Ashleigh Wilson

We don’t get to see many 60s Mustang fastbacks anymore unless they’re Bullitts, Eleanors or painstakingly restored examples with genuine NOS Motorcraft headlight globes. So Justin Stephenson’s head-kicking street brawler is a refreshing breath of tyre smoke, motivated as it is by the ‘Aussie 2JZ’, Ford’s Barra six-cylinder.

First published in the October 2022 issue of Street Machine

Justin didn’t set out with the intention of dropping the now world-famous taxi motor into a ’66 Mustang fastback. “We were at Powercruise in my mate’s 580hp XL wagon and got our arses handed to us by a Cortina with a Barra, so I decided I had to put one in something,” he says. “There are dream cars you think you’re never going to own, and the fastback was one for me.

I found it at a swap meet and thought, ‘If I don’t buy that now, I’ll never get another chance to own one.’”

The Mustang was sent off to the sand blaster and returned in a very sorry state. “My wife said it was a hunk of crap before I bought it, and she was right,” Justin laughs.

It’s a good thing Justin’s damn handy with the hammer and MIG, because the ’Stang needed surgery to or replacement of every panel bar the roof. “Even the inner wheel tubs were rusted out and had been fixed with cardboard and bog like they do in the States,” he says.

Justin spent the next couple of years repairing the shell and preparing the panels for a trip to Champs Bodyworks, where several coats of a custom-mix red, concocted by Justin, were sprayed over the entire car. The fastback cuts a classically mean profile, and under that bulbous nose is enough snot to back up the image.

“Everyone said, ‘You’re not really going to Barra-swap that,’” Justin laughs. But the lure of the boosted six was too strong to resist, and soon Justin had the engine and wiring from a BF F6 in his mitts. A set of Tuff Mounts suspend the
Barra, and the engine’s internals are stock as a rock with the exception of the usual Barra supporting mods: Atomic timing set, ARP head studs, Crow valve springs, Boundary oil pump gears and backing plate, and a Ross balancer.

The team at Spot On Performance were called in to knock up the high-mount manifold that supports the Garrett GTX42 war whistle, along with the intake plumbing, which saw them modifying the intake plenum and fabricating the four-inch exhaust with a single Growler muffler to calm down the angry noises.

Forced Performance extracted a safe 550rwhp out of the stock-internals FPV combo, and though he’s designed the car to make much more, Justin says it’s already an animal on the road.

The transmission is a Powerglide built by Elite Automatics with a Reid extension housing, B&M pan, Torque Power bellhousing, custom ASNU converter and the all-important transbrake. The back of the ’Glide is supported by a piece knocked up by Gazzard Brothers. Universal Driveshaft Services fashioned a shaft to handle the Barra’s torque, while Gazzard Brothers built a sheet-metal nine-inch with a Strange centre, 35-spline axles, Truetrac and 3.55:1 gears to hang from a set of the company’s mono-leaf springs.

Brand-new stock suspension with a set of six-cylinder springs and three-way adjustable Competition Engineering shocks prop up the front end. Wilwood four-pot anchors pull the rocket up after it exits the stratosphere: “I’ve never spent money on brakes before; I’ve always had mismatched crap, but these stop really nice,” Justin says.

Inside the cockpit, you’ll find there isn’t much that’s visually changed since ’66, but practically everything is brand new bar the seat frames and the factory dash pad. The B&M Stealth ratchet shifter, Simpson harnesses, and Powertune digital dash set into a custom carbonfibre panel let you know that this isn’t just a cruiser with a nice set of wheels. “It’s still got all the seatbelts and the harnesses are fiddly, but my 12-year-old insists he wears the harness so he looks cool,” Justin laughs.

This pony is far from a cranky race car, and was built with plenty of both street kays and drag strip passes in mind.

Justin competed in a recent drag-and-drive event and was delighted to discover the Mustang is even economical! “I did the whole three-day event on $120 of fuel – my mate with his 434ci Clevor had to stop at every servo and I was just waiting out the front,” he says.

Even though that event was Justin’s first trip to the strip with the fastback, it hooked up and reeled off a rather tasty 6.6-second PB over the eighth-mile, equating to a low 10 over the quarter – not too shabby for a petrol-sipping streeter!

And a streeter it most certainly is: “The week after, I was running late and couldn’t take the daily, so I jumped in the Mustang with timeslips everywhere and rubber all over it to pick up the kids from school,” Justin laughs.


Paint: Colourfast DIY custom-mix red
Block: 4.0L Ford Barra
Internals: Stock
Valve springs: Crow
Turbo: Garrett GTX42
Intake: Custom
ECU: BF Typhoon
Injectors: Bosch 1250cc
Oil pump: Boundary
Fuel pump: Aeromotive
Cooling: BF radiator
Intercooler: PWR
Exhaust: 4in, Growler muffler
Gearbox: Powerglide
Converter: ASNU
Diff: 9in, Truetrac, 3.55:1 gears
Front: Competition Engineering springs and shocks
Rear: Gazzard Brothers mono-leaf springs
Brakes: Wilwood discs and four-pot calipers (f & r)
Rims: Weld AlumaStar; 15×4.5 (f), 15×8 (r)
Rubber: Mickey Thompson Sportsman 26×6.0x15 (f), Mickey Thompson ET Street
255/60R15 (r)

Spot On Performance; Gazzard Brothers; P.H.Fat Automotive; B&R Restorations; Champs Bodyworks; Mustang Auto Parts; Elite Automatics; Forced Performance; Colourfast DIY Yatala; Jason Stevens; Xavier Smith; Jason Stephenson; Andrew Bradbury; Simon Bailey; John Agnew; Craig Sargeant; my dad; my wife Lyndel and my kids Cody and Liam.