Tony Avedisian, the owner of Tony's Corvette Shop in Gaithersburg, Md., has been working with Corvettes for more than 30 years, so he knows what potential buyers should watch out for.
"My rule of thumb is to look at the body, the frame and the birdcage," he said. "If those things are good, the car is probably restorable or drivable."
Body: Check to see if the original composite body panels (called fiberglass on the early cars and sheet molded compound in later years) has been cracked or tampered with. Is the front clip original, or is it a one-piece aftermarket replacement?
Frame: Corvette frames do rust, but particularly where they kick up over the rear axle.
Birdcage: Many people assume that because Corvette bodies are not steel, rust is no concern. Not so, says Avedisian. The body panels attach to a lightweight metal frame – what he calls the birdcage – that can rust, causing adhesion problems. The best thing to do, as with any old car you're considering purchasing, is to get underneath the car with the flashlight and inspect it carefully.
"Repairing those things is very costly, so it's not a good idea to jump in without knowing what you're getting," Avedisian said.
Those are the basic things a typical Corvette buyer should know about, but Avedisian says that anyone looking for an investment-grade car has quite a bit more homework to do. Meticulous documentation is good, and is indicative of sellers who really know what they're talking about. Research by a potential buyer can go a long way: It pays to set aside passion for a moment and consider a car’s history and hard facts.
The thing to remember, he said, is that there are no absolutes. Cars were built by humans, so small defects and anomalies present themselves quite often. Cars from years when models were redesigned – 1963, 1968, 1984, for instance – are going to show differences between cars more frequently. That’s because GM was fixing problems that popped up as the assembly plant was gearing up for volume production.
"I talked to Tom Hill, who was an engineer for GM back in '63, and he said that he signed three engineering changes a day while they were building the car," Avedisian recalled. "That's a lot of changes."
The trick, he said, to finding a good investment, was to do enough research to narrow down the search to a car or two, then hire a marque expert to look more deeply below the surface. But even then, errors are possible, even likely.
"The stories about a car can get crazy, because someone had the car looked at by a former GM mechanic or something," he said, adding that mechanical savvy doesn't make one a historian, nor vice versa. "Today's evaluation is more forensic than ever. It's a very detailed look to establish the originality of the car, and that's what most collectors want. Not only do the numbers match, but is the grain and broach mark on the block correct, things like that.”