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Point proven: 1973 Dodge Challenger

11 May 2015

Some people say it’s impossible to have a 1000hp-plus street car that’s still nice to drive. Clearly, those people have never seen David Cowan’s Dodge Challenger

Like most others born in the late seventies or early eighties, David Cowan grew up during the boom of the Japanese import scene. Sure, his dad had been a staunch Mopar guy from well before he was born, and David had always had an interest in vehicles of that type, but they seemed far out of reach during his late teens and early 20s. As such, he did what he could and played with the cars that he could afford. Various Nissan Silvias and Mitsubishi VR4s passed through his hands, including a full show-spec version, which, interestingly enough, he still owns.

The older David got, though, the more his attention turned towards the Mopars, inspired by his brother’s 1972 Dodge Challenger project as well as his dad’s 1972 Dodge Challenger Rallye. Being family friends with well-known names in the Mopar performance scene saw him get exposure not only to all sorts of vehicles but also to all sorts of mindsets.  The more time went on, the more David was convinced that if he combined the turbo technology that he was well used to dealing with and the brute muscle of old, he could build a car that’d run single digits on the strip, yet idle around town like a stocker.
The more old boys that he told this to, the more he was told it wouldn’t happen — and the more he knew that he had to prove it could. The plan didn’t kick into action until 2007, when David purchased a 1973 Challenger out of America. The sunburnt-blue, 318-powered car had no idea what lay ahead for it, but over the next two years David collected parts and advice that would soon come into use.

The man David chose to help with the build was Chee Lam of Dynamic Automotive. Those in the import scene will know that name, from his being behind all sorts of high-end show creations as well as many quick street and circuit machines. What he’s not usually associated with is old American vehicles, but, despite his never having touched a Dodge Challenger before, his automotive expertise was easily transferred, even if he did laugh at many parts of the car’s factory engineering.

During the parts collection, David had found an old 440 block, which Scott at Glendene Engine Reconditioners cleaned up for him. He then he ordered a 440 Source 500ci stroker kit, which Chee soon fitted up. The kit included low-compression forged pistons, strong H-beam rods, and an equally tough crank. With the aim of the engine build being to flow as much air as possible, Stealth heads were fitted, along with an Edelbrock manifold and throttle body combo. Each runner of that manifold was fitted with a 2200cc fuel injector, and each spark plug wired to its own MSD coil. An Australian-sourced Haltech Platinum Sport 2000 ECU was chosen to run the whole set-up, with help from an MSD crank trigger.

Fabrication of the exhaust manifolds was handed over to another legend in the Jap-import community, Ronnie Lim. Known as the first man in the country to run a 10-second, then a nine-second, front-wheel drive, Ronnie knows all about creating custom headers, especially ones that hold massive turbos. The pipework that leads from each of the Master Power T70s was also left to Ronnie. The two outlets join together before leading to a massive front-mount intercooler. From here, air is sent around the side of a massive Griffin Radiator and past a custom-machined blow-off valve before entering the throttle body. A Snow Performance water injection kit helps the massive intercooler to drop intake charge temps.

The fuel system did prove to be a slight hurdle. Ironically, the fix involved replacing the expensive high-flowing Magnafuel pump originally fitted with a trio of Bosch 044s. These now effortlessly flow the fuel from one of the largest custom fuel cells we’ve ever seen, but with the car’s appetite for the good stuff, and David wanting the car as a true driver that he could hop into and head anywhere in the country, it does make sense.
When it came time to tune the machine, David knew that, with his choice of ECU, the best person for the job was Australian-based Milos Pavlovic from Top RPM. Known as the tuner of many drag cars, including his own six-second Toyota Celica, Milos knows more about how to get the best out of a Haltech ECU than almost anyone else. Better still, he was stoked at the chance to come to New Zealand and tune the Challenger — so stoked that the fee he charged was a fraction of what it would usually cost.

While David was planning on towing the car to the Revolution Dyno Centre, where the tuning would take place, it actually took Milos less than 10 minutes to fire it up and get it into a drivable state. A few hours on the dyno, and the result of Milos’ tuning magic was an epic 1192hp at the tyres on 20psi boost. Do the maths on that for a second, and take into account the power lost through the Hughes 727 transmission, and you’re looking at a solid 1500 flywheel horsepower!

Of course, not just any trans could handle that abuse, so David asked the one and only “Jandals” to fit it with a full manual valve body and reverse pattern shift kit. Out back is an often underrated diff —  an 8¾-inch stock item, fitted with a tight LSD head — but David was determined to test its capabilities beyond the parameters of what he was told it could do. Holding the diff in place is a Caltrac mono-leaf set-up with Caltrac traction bars below and adjustable shocks above. Up front, the stock torsion bars are still in place, but again matched with adjustable shocks. Knowing that the car needed to slow from the ridiculous speeds it’s now capable of, Wilwood discs and calipers were fitted on each end.

Pure street car it may be, but, with the knowledge that it’ll be run down the drag strip at some stage in the future, David had a full roll cage fitted. Add to this a set of head-restraint-style race seats, Haltech digital dash, and Hurst Quarter Stick shifter, and you’ve got a very serious interior.

That tough look and feel has been carried over to the exterior, where David had Adam and Sonny at Panelworks New Lynn covered every possible surface in a new coat of the deepest darkest black they could find. As a point of difference, the decision was made to leave the overriders on the bumpers; while they’re a love them or hate them item, they do work well with the blacked-out, street-fighter style of the rest of the car. Before the hood was sprayed, Jeff Pullen-Burry was called upon to add the cowl scoop. David’s brother, Matt, a boat builder amongst other things, was tasked with adding the vents in an attempt to reduce under-bonnet temperatures. At some stage in the future, David will use this as a plug to create a lighter fibreglass version, but for now he’s happy with how it is.

As yet, the car hasn’t been down the strip, but it has seen a bunch of street miles, and is remarkably mild mannered on the road. That is, of course, until David puts his foot into it. Then the monster under the hood comes alive and all all hell breaks loose. The old boys who said it couldn’t be done are now eating their words, as the car not only makes more power than their dedicated drag cars, but is lower maintenance and could easily be driven to the track, run similar single-digit passes to them, and driven home again. To us, that sounds like a point well and truly proven. To David, though, this is just the start, as just before this issue went to print, we received photos of the new, bigger turbo set-up being fitted. Looks to us as if, now that he’s proven his point, he’s throwing some salt in the wounds.

Dave’s Challenger was featured in NZV8 Issue No. 114 (November 2014). You can grab a copy here.

Vehicle: 1973 Dodge Challenger

  • Engine: 500ci Mopar Wedge, 1968 440 block, 440 Source stroker kit, forged pistons, H-beam rods, custom Kelford cam, Stealth heads, Edelbrock intake manifold, twin Master Power T70 Q-trim turbos, twin TiAL 44mm wastegates, triple Bosch 044 fuel pumps, Aeromotive fuel pressure regulator, 2200cc injectors, Snow Performance water injection kit, Haltech HPI8 ignition, Haltech Platinum Sport 2000 ECU, MSD blaster coils, MSD leads, MSD crank trigger, custom headers, twin 3-inch exhausts, Griffen radiator
  • Driveline: Hughes 727 transmission, reverse manual valve body, trans brake, billet torque convertor, modified 8¾-inch diff, LSD head
  • Suspension: Torsion bar front, Caltrac mono-leaf rear, adjustable shocks, Caltrac traction bars
  • Brakes: Wilwood discs and calipers all round
  • Wheels/Tyres: 15×8-inch and 15×10-inch steel wheels, 235/60R15 and 29 x 12.5-15 Mickey Thompson Sportsman Pro tyres
  • Exterior: Custom hood scoop, triple black paint
  • Interior: Aftermarket seats, Grant steering wheel, quick release steering hub, Haltech IQ3 digital dash, custom roll cage
  • Performance: 1192hp at the wheels, 20psi boost