NEW YORK (CNNMoney.com) - Sometimes it's a turkey that lays the golden egg.

A list of the fastest-rising muscle cars in terms of auction values includes many cars that are rare and valuable today because, when they were new, nobody wanted them. The list was compiled by Phil Skinner, collector car market editor at Kelley Blue Book.

1969 Chevrolet Camaro

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Of the top 10, four are convertibles with big race-tuned engines. (That number doesn't include one stray two-seat convertible, the Shelby Cobra, that many would not want to count as a muscle car.) That combination was unpopular with buyers at the time for a couple of reasons.

First, it was incredibly expensive. Second, it made little sense: What was the point of buying a high-output engine only to add weight with a convertible top?

Today, most collectors aren't interested in racing these cars. They are bought to be seen (and heard) in. Bigger engines are more desirable than smaller ones and convertibles are more desirable than hardtops. The combination can send prices right through the canvas roof.

Two others cars on the list are "homologation specials," created specifically to qualify a model for the stock-car racing circuit. Nascar rules at the time said that manufacturers had to make a certain number of cars available for sale to the public. The rules didn't say that anyone had to actually buy them, though.

With features like a tacked-on pointy nose and a rear wing that looked like a bus stop bench for giraffes, the Plymouth Superbird evoked more guffaws than awe, even among performance buyers. Dealers accepted the cars into their showrooms because they had to. One that recently sold at auction had never previously been owned by anyone but the dealership. But the Superbird's audacious appearance warms the Hemi-loving hearts of today's muscle car collectors.

These cars are just the tip of a rising market. Not all classic muscle cars command the prices some of these do - well into the six or even seven figures for a few. And, if you want to invest in one that might, experts recommend that you take great care.

As with any other kind of car collecting - perhaps even more, since muscle cars are relatively easy to recreate from parts - documentation means everything.

If you're thinking of buying a specific type of muscle car, suggests Matt Stone, executive editor of Motor Trend Classic magazine, join an owners club and get to know some knowledgeable current owners. And buy the guide books.

Another good idea might be to avoid the big-money makes and go for some of the more overlooked brands, said Stone. For example, among General Motors cars, Buicks and Oldsmobiles will generally command much lower auction prices than Chevrolets and Pontiacs even though all those brands produced outstanding muscle cars.

Even with less expensive cars, said Stone, beware of fakery.

"Caveat emptor all the way," said Stone.

Top ten muscle cars ranked by price increase since 2000

Source: Kelley Blue Book

1. 1971 Plymouth "Hemi" 'Cuda convertible.

2. 1969 Dodge Charger R/T-440 hardtop.

3. 1969 Chevrolet Camaro Z-28/SS coupe.

4. 1970 Chevrolet Chevelle SS-454/LS-6 convertible

5. 1964 Shelby Cobra 289 roadster

6. 1968 Shelby GT-500-KR convertible.

7. 1970 Plymouth Superbird-440 hardtop

8. 1969 Ford Torino-Talladega hardtop

9. 1969 Pontiac GTO "Judge" convertible

10. 1970 Oldsmobile 442/W-30 hardtop

Gallery:Top ten muscle cars as ranked by increase in price since 2000

Source: Kelley Blue Book

Note: As originally published, this story and a related gallery contained several errors regarding details of the vehicles described. We regret the mistakes and would like to thank our readers for helping us correct them.

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