How To: Build Your Own Corvette Grand Sport

March 2021

The early ’60s were a turning point for the high performance world when engineers at Chevrolet, Ford and Chrysler hustled horsepower to maintain track dominance.

It was also a time when legendary engineer Zora Arkus-Duntov secretly developed the C2 Corvette as a cutting-edge racecar—the Grand Sport (GS). The GS featured a 377ci V-8 and an aluminum, tubular space frame for a wicked power-to-weight ratio. Known as the ‘Lightweight,’ GM, sadly, cancelled the project after only five, of a proposed 125, GSs were built making them one of the rarest Corvettes ever. GM ordered the cars destroyed but Zora put away the first two cars, and sent 003, 004 & 005 to John Mecom of Houston, Texas. John sold the three cars to Texans Alan Sevadjian, Delmo Johnson, and Jim Hall respectively.

In the 80s, people were still racing original Grand Sports but they have now become too valuable.

Meanwhile, 14-year-old Charlie Ranfos of Candia, NH was working at his uncle Angie’s Chevron station in Manchester. The station was a hotbed of activity behind which Dave Parris ran small shop hopping-up muscle cars. Sharing the same enthusiasm for Chevrolet performance, Charlie wasted no time in getting into the game once he got his license.

Eventually, Charlie opened Auto Trim, Inc., in Candia, focusing on custom upholstery for classics and muscle cars and C2 Corvettes in particular. His first full restoration was a big-block Mosport Green ’66 roadster followed by a ’67 big-block roadster for his wife Marleen. For himself, he decided to build a GS based on an original Corvette.

Charlie’s search for a C2 donor led to a rolling basket case ’66 coupe sans engine and trans. The chassis was disassembled, blasted and brought to Ron Gagnon at New England Rod Shop in Bedford where it was fully TIG-welded and gusseted for extra strength. Gagnon also crafted a fresh rear crossmember for the updated C3 IRS with 3.73:1 gears, a composite monoleaf and Vette Brakes & Products’ tube shocks. Also added were rear offset trailing arms from Vansteel, Inc. and a factory sway bar.

Up front a manual steering box works flawlessly with updated upper and lower control arms as well as a composite monoleaf and tube shocks along with a factory sway bar. Plenty of braking performance is supplied by C3 Corvette discs and calipers all round. Linking it all to the street you’ll find PS Engineering Grand Sport wheels complete with custom machined hubs with knock-off spinners and safety pins plus BFGoodrich Euro T/A rubber.      

Under the highly sculpted hood resides a 1966 427ci block massaged by R&L Engines of Northwood. It’s fitted with a stock, forged-steel crank and refreshed factory rods topped with forged aluminum Speed Pro pistons. A Comp Cams Street Roller stick sets a heavy beat. A set of World Products’ Merlin iron heads are fitted with Manley Race-Series stainless valves. Up top a 990cfm Stage 3 Holley by the Carb Shop feeds a Weiand dual-plane intake. Ignition is Accel and spent gasses are dumped through a set of Hooker Super Competition headers into 4-inch matching side pipes. The trans is a rebuilt Muncie M22 by Old School 4-Speeds of Springfield, VT.

Mid-America Industries supplied Charlie their GS-2 Grand Sport kit, however, these components from Nevada Classic, LLC are shown for reference only.

When sourcing restyling parts Charlie contacted Mid-America Industries, Inc. for one of their GS-2 Grand Sport conversions who offered nearly everything needed for the visual transformation. Working with good friend Joe Gillooly, the pair started by carefully removing the front and rear clips. To give the car a very distinctive look Charlie had Ron Gagnon work his magic on the hood by adding custom stainless louvers. The doors, trunk, and hood were then fitted and all gaps were dialed in to make sure everything was perfectly balanced. This included modifying the original doors with updated door handle recess panels, installing the fuel filler and glass. From there the pair made the body razor sharp and prepped it for paint by Ron Lavoie at Eastern Auto Body in Manchester. Ron laid down an immaculate coating of PPG Glenn Green accented by a Gold Sand Poly stripe.

The cockpit is all business starting with a custom dash from Mid-America, filled with factory gauges including a stock speedo recalibrated to 200mph. An original Corvette 3-spoke steering wheel carves the course while a Hurst Competition-Plus shifter pulls gears. For comfort, Charlie covered a pair of ’68 Corvette buckets in saddle leather and equipped them with Simpson Racing 5-point harnesses. Inside you’ll also find custom aluminum panels by Mike Curley along with a 4-point rollcage and ATI fuel cell with custom fabbed mounting straps and fill tube by Ron Gagnon.

Throughout the build Mike MacCallister added plenty of mechanical expertise to various areas and Jay Doerfler of Auto Body Specialists in Manchester dialed the car in upon completion to make it road ready. The build spanned more than 1,000 hours over a 15-year journey to create a visually striking C2 Corvette paying homage to the original Grand Sports. Seeing, hearing and watching it in action proves it’s as real a deal as can be.      

Vehicle: 1966 Corvette C2 Coupe
Owner: Charlie Ranfos

• Powertrain
  • Engine: 1966 427ci block
  • Builder: R&L Engines, Northwood
  • Cam: Comp Cams Street Roller
  • Pistons: Speed Pro forged aluminum
  • Heads: World Products Merlin iron
  • Valves: Manley Race-Series stainless
  • Carbs: 990cfm Stage 3 Holley by the Carb Shop
  • Intake: Weiand dual-plane
  • Ignition: Accel
  • Headers: Hooker Super Competition
  • Trans: Muncie M22 by Old School 4-Speeds, Springfield, VT
  • Shifter: Hurst Competition Plus
  • Clutch: 11-inch Hays
  • Master cylinder: GM dual
  • Brakes: Corvette C3 discs and calipers
  • Rear suspension: Updated C3 IRS with 3.73:1 gears
  • Shocks: Vette Brakes & Products
  • Interior aluminum: Mike Curley
  • Upholstery: Auto Trim, Inc., Candia, NH
  • Steering wheel: Stock Corvette 3-poke
  • Seats: ’68 Corvette buckets
  • Harness: Simpson Racing 5-point
  • Roll cage: Ron Gagnon
  • Body panels: Mid-America Industries
  • Fuel cell: ATI
  • Painter: Ron Lavoie, Eastern Auto Body, Manchester
  • Color: PPG Glenn Green accented by a Gold Sand Poly stripe
  • Wheels: PS Engineering Grand Sport 15x8 (front), 15x10-inch (rear)
  • Tires: BFGoodrich Euro T/A P245/50R15 (front), P305/50R15 (rear)