Cars go 8 seconds in the 1/4-mile pretty regularly nowadays – and yes, we’re talking street cars — but few are as cool as Sketch Coleman’s 1971 Ford Falcon XY wagon. Even fewer probably do it with a home-made, rear-mount turbocharging system.
Coleman, who hails from Gold Coast, Queensland, Australia, has owned the Ford Falcon nearly 20 years and driven it as a street machine for most of that. He built it in his shed, or as those of us in the U.S. call it, the garage, and he also said that instead of his neighbor complaining about him working on it, he lent a hand and took care of a lot of the fabrication.
“While we had some down time, I played with the idea of a rear-mount turbo,” Coleman said of his path to boosting his Ford Falcon’s performance. “We started with the stock block and a small single [turbo], which worked better than expected. We ended up collapsing the bore when we pinched a ring, but I had the bug by then.”
As the engine was in need of repair, Coleman enlisted the services of Hi-Torque Performance in Arundel, Australia, to build a new powerplant. It’s based on a Dart Machinery Ford Windsor block that’s been poked and stroked to 427 cubic-inches, but it was topped with 2V Cleveland-style cylinder heads for some massive airflow. The combination was purposely designed to handle plenty of boost.
With a new engine ready to handle whatever Coleman would throw at it, he decided to change the turbocharger to a big single G42-1400 that he mounted up behind the fuel tank. It worked well, but Coleman wasn’t happy that it topped out at 900 rear-wheel-horsepower due to back-pressure.
“The next version was to reduce back-pressure by moving to twin turbos and moving them in front of the differential,” Coleman said of his next iteration of the rear-mount turbocharging setup. “That helped us get 2:1 back-pressure at about 25 psi.”
Engine management is accomplished with a Haltech 2500 EFI system with EGT and knock sensors. Kye Knight provided the calibration, which allows the engine to rev to 5,000 rpm to build boost, and then drops the RPM back down to a lower RPM for the launch. Coleman noted that has dropped the spool time down considerably.
“It’s a heavy car with a cage, and everything fitted, it’s pushing 4,250 pounds, so it takes a bit to get moving,” Coleman noted of his wagon. “It’s running an Allfast Turbo 400 transmission — the weight and power just couldn’t work with the C4 gearboxes, and we went through a few before moving to the GM one.”
With this setup, Coleman ran the “Street Outlaws” event at Willowbank Raceway on 28×10.5 tires. He then went back to the track the following week with a set of Mickey Thompson bracket radial tires mounted up to make some licensing passes and clicked off a 9.09 at 151 mph. Unfortunately, rain prevented him from making more passes that day.
Upon his return to the track, Coleman had a rough start as some of the charge piping came loose. Still, the Falcon clocked a 9.30 at 140 mph, and with the intake tract sealed up, the wagon responded with a 9.10 on 18 psi of boost.
“It was feeling great, so we upped the launch rpm by 100 or so, and dialed in another 4 psi up top to see if we could creep up into the eights,” Coleman said of his next step.
With that change, the Ford Falcon hooked up and headed down track.
“I shifted pretty early and stayed in it until I felt the chute yank me back,” he recalled. “I knew it had to be close and was 100 percent sure when the ladies at the slip box, who have seen me creeping up on it for the last year or so, came out to deliver the news…8.87 at 156 mph! That was fun to pull up before the nets in the old girl. There is a fair bit more to wind in, so I think we are going in the right direction. The next step is to step up the rear housing size and aim for 30 psi boost.”
As you can tell, Coleman is pretty excited by the Falcon’s performance, and he believes there is plenty more left in the combination to trim that elapsed time down further. In fact, he’s hoping for sevens this year.
“We sent a 53-year-old, 4,250 pound work wagon into the eights with a shed-built, rear-mount turbo setup that people said wouldn’t work, and then cruised to get a meat pie in street trim with a little hydraulic roller small-block Ford 427 with 2V CHI heads!” he proclaimed.