Marcy Molkenthen’s Riviera X-11

While she was vending at a car show, Marcy Molkenthen spent all weekend staring at the 1963 Riviera parked opposite her booth. She had always loved the Buick’s design, but after several days of looking at the car she came to the conclusion that she didn’t like the stock B-pillar. Marcy thought the Riviera would be more interesting as a fastback.

While driving home from the show with artist/designer Jeff Allison, the two tossed around the “what if” idea of a prototype Riviera styling exercise with a fastback roofline. A full fictional backstory quickly developed and they dubbed their concept car the “Riviera X-11.” Marcy’s suggestion for long flowing rooflines inspired Jeff to quickly produce a pencil sketch of a 1963 Riviera sporting a 1968 Mercury Cyclone roof.

Neither thought anything much of the discussion or the drawing until a trip to a local junkyard found a Cyclone and a Riviera sitting next to each other. Measurements revealed that both cars shared similar proportions and seeing the two cars side-by-side confirmed that Allison’s sketch had captured Marcy’s vision for a sleeker Riviera. At that moment Marcy decided to build her own 60s styling project that never was.

To Complete the Ruse of the Riviera Being a Concept Car, its Show Display Features Numerous Props Meant to Authenticate the Fake Backstory.

Being a frequent visitor to junkyards nationwide, Marcy quickly sourced the roof from a wrecked 1968 Mercury Cyclone. A running and driving 1963 Riviera was purchased from a fellow Inland Emperors Car Club member and all of the parts turned over to Russ Freund and Darrel Peterson at River City Speed and Chrome in Post Falls, Idaho.

Armed with Jeff Allison’s near encyclopedic knowledge of factory concept car styling cues and River City’s talent for shaping metal, the project began by removing the stock Riviera roof. After sectioning two inches out of the center of the Cyclone top, the new roof went on like it was supposed to be there. The rear quarter glass is from the Cyclone, the door glass from the Riviera, and they lined up perfectly. Getting the fastback to flow smoothly to the newly- fabricated trunk lid took longer than actually fitting the Mercury top to the GM body. With the main feature of the fictitious concept car in place, attention was turned to the rest of the body.

Marcy’s vision for the X-11 included a much smoother hood and cowl than the production version, so a 1963 Cadillac hood skin was wrapped around the stock Rivi hood support structure. The GM styling cue of a pop-up panel to hide the windshield wipers was borrowed from the Mako Shark II Corvette concept car to complete the smooth, flowing look. The stock headlights were hidden behind parking lenses and the chin under the front bumper was painted body color and raised to fill the gap left in the stock design. To complete the front, a square tube grill was fabricated to match the look of the parking light lenses.

The Taillight Lens and Grill Were Fabricated to Resemble a 1965 Grand Prix Unit and Fitted with Thunderbird Sequential Lighting.

Moving rearward, the faux side vents in front of the rear wheel were removed, as were the faux Cyclone roof side vents. A pair of optional ribbed aluminum rocker panels were sourced for the sides, and the exhaust was routed through a square opening just in front of the rear wheels to give a hint of performance look to the concept car. The rear bumper was cut down to a blade-like appearance to match the front bumper.

This left the lower rear quarter panel exposed and unfinished. Another 1963 Riviera donated its rear sheet metal so that its rear fenders could be flipped upside down and side for side to finish this area and give the rear fenders a more symmetrical look. The taillight lens and grill were fabricated to resemble a 1965 Grand Prix unit and fitted with Thunderbird sequential lighting. With the body modifications done, the car was sprayed with PPG Silver as a nod to the silver Buick concept cars of the 60s.

In keeping with the theme of using stock GM parts but giving the car a unique look, Marcy had the car lowered three inches, but kept the suspension stock. Pontiac 8-lug brake drums were fitted to the hubs. A nod to modern performance and drivability came by way of machining the back portion of the front drums away and fitting disc brakes in place of the Poncho brake shoes. Circle Racing from Fresno, Calif. made custom 17-inch wheels to fit the 8-lug drums and Diamond Back provided the custom redline tires in 255/55-17 for the front and 285/40- 17 out back.

Under the hood the stock 401 cu. in. Nailhead got a lumpy cam, new timing gears and roller rockers. A rare Edelbrock Dual Quad intake, the only aftermarket piece that outperformed the stock intake, was found and the logos ground off before it was painted to match the engine as to appear stock. Modern FAST Fuel injection was fitted to give the Riviera good throttle response once its life as a show car is over. A Tremec 5-speed and posi-traction differential from a Buick Wildcat transmits the power to the rear tires.

Turning attention to the interior, stock period-correct materials were used but given updated stitching, pleating and shapes to reinforce the styling concept backstory. The stock wood grain inserts in the dash and door panels were replaced with brushed stainless steel for a more monochromatic look. A stock speedometer was converted to a tachometer and placed in the binnacle where only idiot lights had been in the production car. Vintage Stewart Warner Gauges were given a custom face with an “X-11” logo to match the reworked Speedo and Tach and placed in the radio delete panel. The spare tire is shown off under the large, sloping rear window on its own panel fitted behind the rear seats.

To complete the ruse of the Riviera being a concept car, its show display features numerous props meant to authenticate the fake backstory. Pictures of GM designers with models of the X-11 sit next to actual scale models of the car. Design studies drawn on actual GM styling department paper and an info sign grafted into a drafting table give weight to the fabricated history of the X-11. The car has been shown at the Grand National Roadster Show in Pomona, The Sacramento Autorama and at the Darryl Starbird Rod and Custom Show where it received “Fine Nine” honors.

Despite its recent history and fabricated past the Riviera X-11 is not destined to be just a show car. Marcy incorporated the nods to modern performance in the form of the 5-speed transmission, disc brakes and fuel injection for a reason. After its short life as a show car she intends to put it on the street and participate in autocross events. So if you see a sleeker, smoother 1963 Riviera go by you can believe your eyes, even if you can’t believe the story the owner will tell you.

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