Eric English
June 17, 2013

For Philip Koenen and his crew at Grand Touring Garage (GTG), impressive cars are a way of life. Over the years, GTG has turned out a slew of impressive rides from its original Southern California digs, and now from a much less frantic North Bend, Oregon. The shop's award-winning restorations have taken the main stage at such diverse events as Pebble Beach, Amelia Island, Corvette's Bloomington Gold, and the Mopar Nationals to name a few, but none of those cars have been quite like the '70 Mustang gracing the pages before you. It seems rare that the minds of builder and customer align in near perfect harmony, but such was the case when Koenen was asked to build this one, aptly named the Trans-Cammer.

The owner of this '70 Mustang is a long-time customer of Koenen, and an under-the-radar businessman who prefers to remain behind the scenes. Nevertheless, the build process was very much a two-person brainstorm, with ideas freely thrown back and forth between owner and builder. In the end, it's probably debatable as to whether the Trans-Cammer is best described as a track-worthy street machine, or a streetable track car, but the moniker you hang on it really doesn't much matter. What we do know is that this Mustang is a one of a kind, distinguishable from the crowd, and fully capable no matter the venue. Clearly this isn't the kind of car that's going to rack up thousands of clicks on the odometer, though we'll share that Koenen willingly drove more miles, and placed the car in harms way more than many owners of cars we photograph are willing to do. During our shoot on the beautiful Oregon Coast, we battled for a share of the road with throngs of 18-wheelers, and were run off state property when the car got squirrely on a sand slickened parking lot. Through it all, the Trans-Cammer was composed and did whatever was asked of it.

In case it isn't obvious by now, the inspiration for the name of the car comes vintage Trans-Am racing, but with a 427 SOHC twist. Clearly this is oversimplification, since the car oozes sophistication well beyond '60s ponycar racing, and yet the inspiration remains.

The 427 Cammer powerplant is surely a highlight of the car, and rarely have we seen SOHC motivation paired with the kind of high tech we have here

Regardless, the Trans-Cammer is surely one of the most custom Mustangs we've ever encountered, since aside from the body, there's little that wasn't fabricated completely from scratch. Fortunately, GTG resisted the urge to make major changes to the timeless lines of the '70 SportsRoof body, instead opting for what you could call subtle revisions. Examples include NACA quarter scoops that function to cool the rear brakes, which as Koenen explained, are still the most effective air scoops ever designed. Check out the shaved driprails as well, which vaguely hint at the original gutters rather than complete elimination. Front fenders are fiberglass, and the custom hood is a flyweight 12 pounds thanks to carbon-fiber construction. The flawless body and paint is the handiwork of Jon Byers, Alan Donald, and Paul Iozzio at Byers Customs in Auburn, Washington, who when all was said and done, sprayed the sheetmetal in the blackest of black two-stage PPG.

Photo Gallery

View Photo Gallery

The 427 Cammer powerplant is surely a highlight of the car, and rarely have we seen SOHC motivation paired with the kind of high tech we have here. Needless to say, it works, with said engine assembled by G-Force Racing Engines in Paso Robles, California. There, the late SOHC guru, Bud Gilbert, stayed mostly true to original FoMoCo save for JE Pistons, Manley rods, and Ferrea stainless valves. Before opening G-Force, Gilbert was an engine-building phenom for years at Louis Unser's engine shop, so you know this one is dialed in. Despite backing off the compression to run on pump gas, the 427-cuber made an even 600 horses and 525 lb-ft of torque through the mufflers on the G-Force engine dyno. Custom headers and dry-sump oiling are more noteworthy additions, with the whole affair backed by a TKO 600 five-speed and a full floating 9-inch rearend.

Much as the entire car is a tour de force, we're particularly nuts about the interior, a place of utility, race car function, and craftsmanship all rolled into one. The dash was shaped from sheet aluminum by Fast Eddies in Orange, California, and filled with Auto Meter gauges and appropriate switches. Floor surfaces effectively blend silver-painted sheetmetal with high-temp insulation and custom rugs, and mount Cobra buckets and a one-of-a-kind center console. Combined with a full cage, Wilwood pedal assembly, and ididit tilt column, the result is as creative and cool as it gets.

Much of the genius of the Trans-Cammer is well hidden, and yet a big part of the car's performance potential. A full frame designed by GTG and fabbed by Fast Eddie's Ed Larnard allows for a no-compromise suspension, a massive nine inches of engine setback, and an ultra low stance. The front end consists of 2-inch drop spindles, chrome-moly control arms, Penske adjustable shocks with Hyperco springs, Speedway Engineering antisway bar, and an ultra-quick Woodward rack-and-pinion assembly. Out back is a triangulated four-bar setup with more critical hardware from Penske, Hyperco, and Speedway. The custom chassis and floorpan also allows for the trick exhaust that tucks up behind the rocker panels. GTG's Jeff Yost spent untold hours hand fabricating the 3-inch diameter mufflers and exhaust system, not to mention the engine compartment sheetmetal and a litany of other technical details.

While this wild Mustang admittedly hasn't yet turned a lap for time, Koenen surely didn't build the car to sit idle. The build reflects top drawer quality, but that doesn't have to equate to static display. We witnessed that street miles aren't an issue, thus have reason to believe the car will get a thrashing when the timing is right for the parties involved. We sure hope so anyway, for this one clearly deserves—no, this one clearly demands to be uncaged.

Photo Gallery

View Photo Gallery

The Details
'70 Mustang SportsRoof
Builder: Philip Koenen, North Bend, Oregon

Engine
427 cubic inches
'65 427 SOHC block
4.23-inch bore
3.78-inch stroke
Ford forged steel crankshaft
Manley connecting rods
JE forged pistons
Ford factory SOHC iron heads, Ferrea valves
Ford factory SOHC dual quad aluminum intake
780-cfm Holley 2-4s
Ford distributor with electronic conversion
Aviaid dry sump oiling system

Exhaust
Custom 2-inch headers by Keith Hickson
3-inch exhaust and hand-fabricated mufflers by Jeff Yost

Transmission
Tremec TKO 600 five-speed
McLeod 11-inch clutch, pressure plate, and hydraulic throwout bearing

Rearend
Ford 9-inch with Mittler Brothers hubs and full-floating axles
Traction-Lok differential
Strange nodular carrier
4.11 Richmond gears

Suspension
Front: 2-inch drop spindles, chrome-moly control arms, Speedway Engineering 1¼-inch antisway bar, Hyperco 500 lb/in springs, Penske adjustable shocks, Woodward rack-and-pinion
Rear: Triangulated four-bar with Speedway Engineering 7⁄8-inch antisway bar, Hyperco springs, Penske adjustable shocks

Brakes
Front: Baer disc, six-piston calipers, 14.75-inch drilled/slotted rotors
Rear: Baer disc, six-piston, 13-inch drilled/slotted rotors
Wilwood proportioning valves, brake pedals, CNC master cylinders

Wheels
Front: GTG–designed billet aluminum centers, assembled by Vaughn Machine, 17x9.5
Rear: GTG–designed billet aluminum centers, assembled by Vaughn Machine, 17x11

Tires
Front: BFGoodrich g-Force KD, P275/40ZR17
Rear: BFGoodrich g-Force KD, P315/35ZR17

Interior
Fabricated aluminum dash with Auto Meter gauges, custom console, ididit tilt column, Momo steering wheel, Cobra seats, upholstery by Thornton Auto Upholstery, Electric Life power windows

Exterior
Body and paint by Byers Customs, Auburn, Washington; PPG two-stage black paint; functional NACA quarter scoops; carbon-fiber hood, mirrors, front splitter, and rear diffuser; fiberglass fenders, bumpers, and trunk lid with Gurney lip

Chassis
Frame and rollcage designed by GTG and built by Fast Eddie's, Art Morrison outer framerails