Muscle Reimagined

Modern Rodding Feature

InTheGarageMedia.com

Marc Grondahl’s 1969 GTO is Transformed With a Roadster Shop Chassis and LS3 Power

By CHUCK VRANAS

Photography by THE AUTHOR

H

eralded as “The Great One” in advertising brochures for 1969, Pontiac focused on separating its GTO from the heavy competition for muscle car supremacy by showcasing its wide-track performance and road-hugging capabilities. This was further personified by the proclamation of it being a “Master of Macadam” thanks to several engine and transmission options to let it dominate regardless of whether it was on the street, strip, or carving its way up a mountain pass. Coupled with the visual dynamics of a color-matched Endura front bumper, long flowing hood, curvaceous bodyline, and luxurious interior, it’s easy to see its charm. The 1969 model laid out across Modern Rodding pages, owned by Marc Grondahl of Rye, New Hampshire, showcases the latest performance upgrades and a fantastic story.

There’s nothing quite like a classic 1960s-era muscle car convertible for cruising the coastline with the sun shining above while the sounds of surf fused with a rumbling exhaust note create a perfect chorus. Having grown up in the middle of the muscle era, Marc’s passion for a drop-top GTO led him to start looking for the right ride to bond with. Long before he began his search, an original numbers-matching Warwick Blue Poly 1969 with a 400ci V-8 passed through a national auction with the prominence of having once been owned by actor Val Kilmer. The car was quickly scooped up and was again presented for sale a few years later when a good friend, Jim Dunaway, general manager of Bayberry Vintage Autos (BVA) in nearby Hampton, presented it to him to check out as it was ready to hit the auction stage once again. The car, however, was now black, having undergone a full restoration with a Pro Touring twist by Area 51 Restorations in Ontario, California, while still retaining its original engine, frame, and roots tracing back to Kilmer’s ownership. Without wasting time, a high bid was placed to secure its new home.

Once back in New Hampshire, Marc enjoyed cruising it along the coast for a season, but he still yearned for more power and improved handling to bring it up to current standards. Having worked with Dunaway at BVA on two prior builds, the pair shared many of the same ideas for bringing the car to the next level with a chassis, driveline, and interior upgrade. With a plan in place, the car was delivered so the BVA team could get started on the transformation. Seeing the original restored frame and driveline were in mint shape upon disassembly, a decision was made to sell off the roller and contact Roadster Shop (RS) to prepare the car for plenty of cutting-edge handling. Marc selected one of their masterfully crafted SPEC-series chassis showcasing their exclusive CNC laser cut and contoured framerails (stepped front and rear), complete with custom crossmembers and bracing. For ease of installation, RS also utilizes all factory mounting points for body, bumper, and core support mounts, as well as offering crossmembers and chassis bracing, allowing for up to a 3-inch exhaust.

front seats and steering wheel of 1969 GTO

Focusing out back, a Ford 9-inch housing with 31-spline axles from Strange Engineering links to a Pro-Series nodular iron third member spinning 3:70 gears matched to an Eaton Detroit Truetrac differential. It’s secured in place by an RS parallel four-bar combined with matching RS SV single-adjustable coilover shocks by Fox. For industry-leading handling, RS IFS showcases their exclusive boxed lower control arms with tubular uppers matched to Wilwood ProSpindles, RS SV single-adjustable coilover shocks by Fox, power rack-and-pinion steering, and heavy-duty sway bar. When it’s time to shave speed, a Wilwood dual master pushes fluid through stainless lines to Baer Pro+ 14-inch drilled-and-vented two-piece rotors with matching six-piston calipers mounted at each corner. To add just the proper bite linking it to the street, a set of Schott Mach V-Series wheels, sized 18×9, wear Nitto NT555 G2 rubber sized P245/35R18 front and P285/35R18 rear.

When it came time to turn up the heat underhood, a call was placed to Don Hardy Race Cars (DHRC) for one of their fire-breathing LS3 V-8s packed with a speed shop full of punch, bringing it to the next level. To start, a cast-aluminum block with six-bolt, cross-bolted main caps was filled with a nodular iron crank linked to forged 4340 steel I-beam rods wearing hypereutectic aluminum pistons getting bumped by a custom DHRC cam. Up top, a set of aluminum L92 cylinder heads as-cast with 68cc chambers meet a Holley EFI LS single-plane intake crowned with a matching Terminator X Max EFI managed by Holley Dominator electronics to deliver the power. It all comes to life through a factory ignition with exhaust ripping through a set of stainless Ultimate Headers to a custom 2-1/2-inch stainless exhaust with Black Widow mufflers, all crafted by BVA. To move the goods, a GM 4L80E trans links to a custom driveshaft.

There’s nothing better than a body that’s been meticulously restored to make a build easier. When the team at Area 51 Restorations took on the rotisserie restoration of the original factory sheetmetal, it was apparent the car had seen its share of abuse through the decades, leaving it needing attention. Once stripped, they determined what could be salvaged (including the floors) and followed with a call to Original Parts Group (OPGI) to order plenty of freshly struck steel to take on the project. Replacement metal starting in the back included quarter-panels, rockers, doors, fenders, and hood. From there, the body was gapped to perfection and metal finished to prepare it for a decadent House of Kolor Triple Black gloss coating, bringing it back to life.

To add the right amount of allure to the interior, the restored factory dash was treated to a set of Dakota Digital VHX dials to monitor the vitals. At the same time, a Spindle-Series steering wheel from Sparc Industries navigates through a factory column. Shifts move through a Lokar stick while cool breezes are compliments of Vintage Air, all coming to life through an American Autowire system installed by BVA. For a perfect complement, the team at GCD Auto Studio of Florida, New York, worked their special magic in crafting a business office with a classic look. Custom seating with matching side panels and a flowing console showcases an immaculate design accented by yards of Relicate black leather with suede inserts and plush black carpeting. GCD also gets credit for restoring the convertible top and crafting the new rear boot. Marc has already laid down plenty of miles while giving the GTO’s newfound power and performance a workout, and to us that’s as good as it gets!

Modern Rodding

VOLUME 5 • ISSUE 51 • 2024

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