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Green Mamba: A Wild 1968 Pro Touring Corvette

Aesthetics That Move: 1968 Corvette built to wow sitting still or dodging cones

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Autocross has become quite the popular sport among weekend car enthusiasts and its popularity these days means the landscape of vehicles competing is drastically varied. It’s still a great way to bring out your newer Camaro or Corvette and see what she will do or even give it a go in your classic muscle car. But with time, competition and rivalries arise and it takes more than a decent driver in a 2010 Camaro SS to bring home top honors nowadays. It’s all about purpose-built late-model rides and hard-core Pro Touring muscle. Anything short of that and you’re stuck at the kid’s table.

Bob Bertelsen of Columbiana, Ohio, has been around the autocross scene long enough to know that. In fact, he’s built a few different machines that have seen time weaving through cones in parking lots, such as his 1971 Camaro and 1969 C10 pickup. While they were both plenty fun to drive, the competition wasn’t slowing down and he needed something new to keep him in the game. That’s when he decided on a Corvette. Some of the leading autocrossers were running late-model Corvettes, but there was no appeal to Bob in just buying his way onto the podium with a newer car and some performance upgrades. No, he wanted to build something. He ended up settling on a 1968 Corvette for its short wheelbase and potential for a seriously good power-to-weight ratio.

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Bob found the Corvette in Columbus, Ohio, and purchased it back in the fall of 2014. According to Bob, “The previous owner told me they were the second owner and knew the first owner. He said the car was stored every winter and the car had not been driven since the early ’90s.” Spending winters in the garage and only having two previous owners fared well for the Vette because once Bob got to tearing the car down, he found the frame to be in pristine condition.

Around the same time as his purchase of the car, Bob had been in contact with Kyle Tucker of Detroit Speed Inc. regarding a suspension system for C3 Corvettes. They didn’t have anything on the market just yet, but Kyle and Bob struck up a deal to use Bob’s ’68 to mock up their first prototype suspension system. The car then sat for a while as the guys at Detroit Speed started the design and build process of the suspension components on their own C3 test mule. Once they had the front and rear suspension figured out, they made a complete prototype set and Bob sent his Vette over to their shop in North Carolina. Detroit Speed test-fitted the parts to Bob’s unmolested chassis, making a few changes here and there. Finally, in May of 2016 Bob got his car back.

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What he got was the Detroit Speed C2/C3 SpeedRay suspension package up front along with their C2/C3 DECAlink independent rear suspension (IRS) out back. The system utilizes Hypercoil springs with JRi double-adjustable shocks all around while the spindles, A-arms, and antisway bars were designed in-house by Detroit Speed. The DECAlink IRS features Detroit Speed’s Hammerhead 12-bolt rearend with a 3.55:1 gear and Detriot Truetrac limited-slip.

Back from Detroit Speed, Bob chose a set of Baer Brakes 6R disc brakes for all four corners. The 14-inch rotors and six-piston calipers with Detroit Speed’s brake bias control would give Bob all the stopping power and adjustability he needed.

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The next big step for Bob’s Corvette was bodywork, but since form follows function, his choice of wheels and tires were mounted first. He went for a set of Forgeline CV3s measuring 18x11 in the front and 18x12.5 in the rear, wrapped in BFGoodrich Rival S 315/30R18 and 335/30R18 tires front and rear, respectively. With the wheels and tires mounted he could get the look and stance he desired while still leaving adequate room for suspension travel.

So, about all those body modifications. We would have to keep you here all day to fully explain all the work that went into every detail so we’ll do our best to keep it semi-concise. With the Forgeline wheels in place, Bob fitted some fender flares he had previously purchased, but the wheels still protruded past the edge of the flares. He then modified the flares and extended them to clear the tires. It was the hood’s turn next where Bob grafted late-model ZL1 hood vents to the ’68 hood then re-engineered the stock C3 side vents to match. Bob’s focus then shifted to the trunk and rear window. “I always felt the rear deck on a C3 Corvette looked a mile long, so I decided I would slope the back window,” Bob told us. And while he was at it, he cut the rear deck and made a trunk with CAD-designed and CNC-machined aluminum hinges. Back up front, Bob decided to rid the Corvette of its popup headlights so he filled the gaps with fiberglass and fitted custom billet mounts for each side that would house a total of 14 LED lights. Bob put some final touches on the exterior with carbon-fiber bumpers, splitter, rear wing, and side-view mirrors.

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And of course, we can’t forget about the paint. To really make sure his Vette stood out, he made a custom mix with BASF R-M and called it Green Mamba, which he also ended up naming the car. Pro Comp Customs of Glenshaw, Pennsylvania, were then tasked with doing the final bodywork and paint.

Remember, this build is about more than just looks so under the hood is one seriously potent LS7 built by Kurt Urban, now of SDPC Raceshop, the custom engine build shop of Scoggin-Dickey Parts Center. The 427-cubic-inch mill saw a complete rotating assembly with Diamond flat-top pistons along with Callies Compstar crankshaft and rods. The camshaft is a custom grind spec’d by Kurt Urban Performance for this specific engine. The LS7 is topped with a FAST LSXR 102mm intake and throttle body and is controlled by a Holley Dominator ECU. With the above upgrades to the LS7 and 11:1 compression, the engine puts out 650 horsepower at the flywheel and will rev all the way to 7,500 rpm.

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Since Bob would be running the Vette hard on track, the LS was retrofitted with a Dailey Engineering dry-sump setup. Bob then had Hickey Metal Fabrication of Salem, Ohio, laser cut the aluminum pieces he needed to build a remote oil tank that would bring the system capacity up to 3 gallons. Then, to keep the engine temps under control, Bob installed an aluminum radiator from C&R Racing. Finally, the exhaust system is comprised of custom 1 7/8-inch headers going into stainless steel pipes and out 4-inch side pipes from Hooker.

Behind the LS7 is a Bowler Performance Stage II TREMEC Magnum six-speed transmission. Transferring power between the two is a Centerforce Triad triple-disc clutch inside a Quick Time bellhousing. Bob also added Auto-Blip, which gives him an auto-rev-matching ability. Just press the brakes going into a corner, apply the clutch, then utilizing a drive-by-wire throttle the car will automatically blip the throttle for a silky-smooth downshift.

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Going inside the cabin of Bob’s Corvette, the main talking points are the custom dash, center console, and door panels done by Trick Labs of Butler, Pennsylvania. The Cobra seats were re-covered in black leather and perforated suede to match. Instead of your classic gauge cluster behind the steering wheel, Bob opted to go high-tech with two digital displays in the center console. The top display is from AutoMeter and feeds Bob all the information he needs to know via the Dominator ECU. Below it is a touch screen Samsung tablet that is used for navigation and to play music through Bluetooth-controlled Kenwood speakers. Just below the tablet are his Vintage Air controls for heat and defroster. As far as driving controls, a Detroit Speed MPI steering wheel and NRG quick-release hub is connected to an ididit steering column.

The whole build—once Bob got the car back from Detroit Speed—took just over a year to complete in his two-car garage. Before long, he was getting to try out his new Pro Touring, autocross beast for the first time. After just a couple sessions on a road course and autocross the car more than met his expectations. “Man, this thing will do more than I thought it would!” was his first reaction. But how will the car fare when stacked up against the big dogs? “With a little more seat time, I will be nipping at the leaders’ heels,” Bob stated confidently. Time will have to do the telling, but we, too, think he’s got a pretty good shot.

Photos by Robert McGaffin


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