Upgrading a ’66 GMC: From Classic to Supercar Handling

By Chuck Vranas – Images by the Author

There’s nothing better than staying in tune with regional shops across the country for Classic Truck Performance. Frequent visits to many of them gives us the opportunity to follow new builds as they move forward from their basic starting points while focusing on the progression of design elements fused with plenty of custom fabrication and industry-leading parts. Our latest stop brought us back to Chris Cerce Customs (CCC) in Taunton, Massachusetts, to check out the current projects laid out across the shop being worked on, including one particular ’66 GMC pickup for customer Rob Challie that’s receiving the full custom treatment to prepare it for a fresh start this year.

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02 Assembling the frame for a 66 GMC truck in a workshop

Entering the massive 9,500-square-foot shop you’re immediately consumed by the final assembly area filled with a number of projects moving toward completion. With CCC handling everything from the initial concept embodying a truly contemporary flair perfectly blended with cutting-edge performance from an updated platform and hopped-up LS driveline, the evolution of the GMC promises to be another noteworthy build to roll out of the shop. Shadowed by Layla, the ultimate shop dog, we wasted no time in getting up close and personal with the freshly minted chassis to delve into just what makes it so wicked.

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From the beginning, the GMC was destined to be a tire-scorcher with supercar handling capabilities on tap from front to rear. Bringing it to the next level started with platform selection and its distinct needs brought the team to Rothspeed in Milton, Vermont, for one of their hand-fabricated, high-performance IRS chassis offerings. Creating a stout base capable of handling the newfound horsepower demands commenced with a custom frame showcasing their exclusive fabricated 2×4-inch steel framerails with integrated internal X-rail design at all suspension mounting points. There’s plenty of magic out back with Rothspeed’s dynamic IRS assembly loaded with neat features, including their custom billet differential housing packed with a Strange Pro Nodular Iron third member with 3.73 gears, Wavetrac differential, and 35-spline chromoly 4340 CV shafts. It’s all secured by a combination of Rothspeed billet upper and lower control arms linked to matching billet spindles along with JRI double-adjustable coilover shocks with remote reservoirs, Hyperco springs, and a 1.25-inch splined sway bar.

04 Detailed view of the rear suspension on the 66 GMC truck frame

For razor-sharp handling you’ll find matching Rothspeed billet upper and lower control arms deftly matched with billet spindles, JRI double-adjustable coilover shocks with remote reservoirs, Hyperco springs, and a 1.25-inch splined sway bar all working through a Detroit Speed & Engineering (DSE) power rack-and-pinion steering. It all comes to life thanks to a lustrous coating of vibrant red powdercoat with all suspension components wearing a complementing deep charcoal. Need to drop speed on a dime? A set of Wilwood 14-inch Superlite 6R drilled-and-slotted discs with six-piston forged calipers in front matched to 13-inch Superlite 4R rears with drilled-and-slotted discs and four-piston forged calipers get the job done. Hitting the street, you’ll find a set of Schott FUEL d.concave–series wheels sized 20×10 in front and 20×12 capped with Michelin Pilot Sport rubber, sized P285/35R20 and P345/35R20 respectively.

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05 Rear angle showing the differential on the 66 GMC truck frame

To turn up the heat, check out the Don Hardy Race Engines (DHRE) built 427ci supercharged LS pumping out a tire-melting 947 hp. Packed with all the right bits, the engine features a Dart SHP LS block and heads matched with a DHRE cam and knockout punch coming from a Whipple 2.9L supercharger. A Holley Dominator fuel injection and electronics, CCC custom air intake, and a Wegner accessory drive keeps it all moving, matched to a DHRE-built 4L80 trans. Exhaust flows through a set of Holley high-flow exhaust manifolds to a custom CCC-fabricated 3-inch stainless exhaust with custom X-pipe and Borla ProXS mufflers, which is a work of art in itself.

06 Polished differential installed on the 66 GMC truck frame

Check it out: Building a Modern 9-Inch Rearend With Strange Engineering

When it came to addressing the cab and bed, the CCC team had plenty of tricks to add to the formula. Starting underhood they fabricated a custom firewall, inner wheeltubs, radiator core support, and cowl, following to the rear by crafting a custom bed structure and floor. We’re just scratching the surface on this cool GMC. Just wait till our shoot of the completed truck to follow in an upcoming issue!

07 66 gmc suspension upgrade 08 Bright red engine being mounted on the 66 GMC truck frame 09 White cab mounted on 66 GMC truck frame with a red engine 010 Rear view of the 66 GMC truck bed under construction 12 Detailed view of rear suspension and differential on 66 GMC truck 013 Yellow 66 GMC truck cab and bed undergoing restoration 014 Rear view of 66 GMC truck bed with metalwork 015 Exhaust system installation on 66 GMC truck frame 016 Complete rolling chassis of 66 GMC truck with red frame 017 Rear suspension and exhaust details on 66 GMC truck frame 018 Front view of the 66 GMC chassis with red engine and black headers 020 Dual exhaust system on 66 GMC chassis with polished mufflers 021 Detailed front suspension of 66 GMC chassis 022 Rear suspension with RideTech system on 66 GMC 023 Complete rolling chassis of 66 GMC with red frame 024 Black 66 GMC truck with red engine in the workshop 025 Engine bay of black 66 GMC truck showing red GMC engine 026 Rear view of 66 GMC truck chassis with black body and red frame