As spring emerges across much of the country, classic car aficionados are uncovering their vehicles and taking them out for a spin. Some of the more popular classics include the Ford Mustang GT, Chevrolet Corvette convertible and the Dodge Charger R/T coupe.

Black Book, which provides independent vehicle pricing to the automotive industry, had their valuation specialists analyze a number of cars, and what they found might make you think twice about the vehicle you purchase today and its possible worth in the future.

The manufacturer's price for these and many other classic vehicles was usually under $10,000, but in today's market, they can be valued at anywhere from $100,000 to well over $1 million. Why are they so valuable?

“What makes a car a collectible over time includes any number of factors that include popularity, pop culture, and production volume,” said Eric Lawrence, director of specialty products at Black Book. “Many people think today's uber-expensive vehicles always came with a hefty price tag, but these vehicles show that's clearly not the case.”

Here are 12 cars identified by Black Book that may have had rather inauspicious beginnings, but are definitely considered classics today by collectors.

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(Photo: Black Book)

12. 1965 Ford Mustang GT

Trim:  289/271hp

Body style:  Convertible

MSRP:  $3,156

Current value:  $68,500

Increase in value: 2,100 percent

(Photo: Black Book) 

11. 1957 Ford Thunderbird

Body style:  Convertible

MSRP:  $3,408

Current value:  $85,000

Increase in value:  2,900 percent

(Photo: Black Book) 

10. 1969 Chevrolet Camaro

Trim:  Z28

Body style:  Coupe

MSRP:  $3,184

Current value:  $95,000

Increase in value:  2,900 percent

(Photo: Black Book)

9. 1957 Pontiac Bonneville

Body style:  Convertible

MSRP:  $5,782

Current value:  $175,000

Increase in value:  2,900 percent

(Photo: Black Book) 

8. 1968 Dodge Charger R/T

Trim:  Hemi 426

Body style:  Coupe

MSRP:  $3,937

Current value:  $135,000

Increase in value:  3,300 percent

(Photo: Black Book) 

7. 1967 Chevrolet Corvette

Trim:  427/435 hp

Body style:  Convertible

MSRP:  $4,677

Current value:  $165,000

Increase in value:  3,400 percent

(Photo: Black Book 

6. 1959 Cadillac Eldorado

Trim:  Biarritz

Body style:  Convertible

MSRP:  $7,400

Increase in value:  3,500 percent

(Photo: Black Book) 

5. 1965 Porsche 911

Body style:  Coupe

MSRP:  $6,490

Current value:  $250,000

Increase in value: 3,800 percent

(Photo: Black Book) 

4. 1948 Chrysler New Yorker

Trim:  Town & Country

Body style:  Hardtop

MSRP:  $2,725   

Current value:  $140,000

Increase in value:  5,000 percent

(Photo: Black Book) 

3. 1971 Pontiac GTO

Trim: Judge

Body style:  Convertible

MSRP:  $4,070

Current value:  $225,000

Increase in value:  5,400 percent

(Photo: Black Book)

2. 1967 Shelby Cobra

Trim:  427

Body style:  Roadster

MSRP:  $7,500

Current value:  $1.3 million

Increase in value:  17,000 percent

A 1971 Plymouth Barracuda convertible sells for $3-5-million. (Photo: Mecum Auctions) 

1.  1971 Plymouth Barracuda

Trim:  Hemi 426

Body style:  Convertible

MSRP:  $7,500

Current value:  $2.5 million

Increase in value:  58,000 percent

A number of factors affect the value of these cars, including the condition of the vehicle, how well it has aged, what flaws it may have in the body, the type of replacement parts used to repair it, the mechanical condition it is currently in, whether it has factory or aftermarket options, and the type of transmission. It is also important to document any repairs or improvements, since they will also affect the value of the vehicle.

Classic vehicles are generally more than 10 years old and have particular historic interest because of exceptional workmanship or because their production was limited in some way. Any vehicle more than 25 years old is considered an antique.

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