Las Vegas, Nevada – We never need an excuse to talk about an early C3 Corvette. But when we spotted this incredible Pro Touring 1968 Stingray in the Atech Motorsports booth during the 2025 SEMA Show, we started writing this article almost instantly.
Aptly nicknamed “The Green Mamba”, this custom Corvette is owned by Bob Bertelsen—and as you may have guessed he’s really into motorsports, having built, owned, and driven a number of incredible performance cars in his past.
The Green Mamba is a stunning example of his talents—built in his home’s two-car garage, no less.
While Bob’s built and raced an impressive portfolio of cars, until this C3 arrived, he’d never tackled a Corvette project.
But it was easy to see the appeal of the Stingray chassis.
“I was looking for the ability to turn tight and corner well,” Bob explains. “It’s a shorter wheelbase and had the performance characteristics that I knew I could get out of it, primarily for autocross.”
Now on the hunt for a Corvette, Bob found a 1968 Corvette Stingray for sale nearby.
“It was kind of clean, paint was nasty, but it was a solid car,” he admits. “I didn’t even drive it. I just drove it off the trailer, into the garage, and that was all the farther it got, the motor, transmission—everything was coming out.”
Speaking of motor, under the Green Mamba’s hood is a race-prepped 427ci LS7, with an upgraded rotating assembly bumping compression to 11:1.
There’s also a FAST LSXR Intake/throttle body combo, dry sump oil system, Holley ECU, and Hooker Headers ending in oh-so-appropriate side pipes.
That LS7 is backed up with a Tremec Magnum six-speed manual prepped by Bowler Performance Transmissions too, aided by a Centerforce Triad clutch—though it may not stay that way.
“I’m actually contemplating going to either an 8HP70 or 8HP90 transmission, or the BMW DCT dual clutch,” Bob tells us. “I left foot brake when I autocross. So to downshift or upshift, you got to move your feet. Not a big deal, but it also takes probably a couple tenths. DCT will shift in about 200 milliseconds, and I don’t have to move my foot off the brake.
“And that matters. I’ve won by a couple thousands, 800 thousands. You know, I mean, it can be tight. So anything I can do helps.”
But the drivetrain is only a slither…err….sliver of the magic here.
Bob tossed on a veritable smorgasbord of performance parts, including plenty of then-prototype suspension upgrades from the gang over at Detroit Speed.
“Detroit Speed was just coming out with their Corvette suspension, and that’s what’s on here,” Bob reveals. “They developed it on their car, but they were looking for another car then to test fit and see if it still would work, and can it be installed with the body on. And this car actually went to Detroit Speed.
“So if you look at the installation manual, the pictures of the frame and install are actually this car.”
Those performance upgrades might just be overshadowed by the wild custom body mods on this 1968 Stingray.
From the front splitter to the rear wing, everything has its purpose. In fact, Bob worked with Robby Unser (yes, THAT Robby Unser) to help develop functional aero all around. That massive rear wing was a recent addition, along with some key modifications to the front splitter.
“I learned a lot about aerodynamics from Robby,” Bob says. “How much opening do you have in the grill? You have to have this equal amount coming out of the hood to get it out from under the car. It’s creating lift.
“Same with the pockets where it brings air up in the wheel wells. So we put vents on the wheel wells and also the back of the wheel wells are vented out the side now. So we’re trying to move air where it belongs and keep it where it belongs.”
The original build was finished in 2017, and Bob raced it successfully for years before building an earlier C2 Sting Ray Corvette, which he dubbed “Solar Flare.”
But the Green Mamba didn’t hiss off into a corner.
“Solar Flare had the same suspension, drivetrain—except for the addition of ABS, everything was identical,” Bob explains. “And I raced it some, probably about a year and a half, and I was home complaining to my wife that I’m just not winning. I’m in the top three, but I’m not winning like I was with the Green Mamba.
“And she’s like ‘You’re faster in your green car,'” Bob chuckles.
“I’m like, no, I think people are just faster and I’m getting older. She says ‘Take the green car.’ So I went to UMI for an autocross event, and right out of the gate, the 1st to 2nd turn, it’s like, this car is quicker. And I knew it.
“And then I went home. I’m like, ‘Honey, you were right. It’s a much faster car.'”
So Bob admits that the Green Mamba might be here to stay. But before we said goodbye, we had to ask him about the inspiration for the name.
“So all my cars that I’ve raced have been bright colors, but I hadn’t done a bright green, and then I do a contest to name them,” Bob laughs. “So I put it out just in an e-mail, people that follow, or I think this one might even been on Facebook. And Green Mamba just sort of stuck out, it’s aggressive snake, you know.”
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Special Hat Tip to Atech Motorsports’ Scott Hunter for making this interview happen.
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