When choosing an older car to purchase or restore as an investment, remember there are old cars and then there are OLD CARS. There are several reasons that a 1959 Cadillac is worth much more than a sixties model. Using this car as an example, and there are many others, some of these differences will become apparent.
Currently a 1959 Cadillac convertible in very good investment grade condition sells for $45,000 to $80,000. The 2-door hardtop version ranges between $4800.00 to $10,000.00, while the 4 door sedan is valued between $4,000 to $8,000.00. The very next year, 1960, the same models are valued at an average price of $16,500.00 for the convertible, $4,00.00 for the 2-door hardtop and about the same for the 4 door sedan. The prices continue to fall each year thereafter as the height of the fins decrease.
First the 1959 Cadillac was a "landmark" car. It was a big, heavy car with large motor and gaudy styling. It was so different that Hollywood Stars of that time immediately accepted it and it became a symbol of good times, wealth, and of the excesses of the late fifties.
Second, the rarity of the car is always a major factor. Of the 142,272 1959 Cadillacs produced, only 11,130 units were the 62 series convertible. Convertibles have the potential for excessive rusting problems, and this has further deceased the surviving cars.
Third, the models within the same year fluctuate widely with the sportier models always being more valuable. The convertible is almost universally considered the sportiest car in the lineup and usually commands the highest prices. The 2 door hard top is also considered more good-time oriented, particularly if it has a high performance package. Most 4-door sedans are considered a "family" car and as a result they usually have the highest production numbers by far. They usually are the least desirable and therefore the least valuable of the cars produced within the same model year.
Therefore, the 1959 Cadillac Convertible is the most valuable because it is firstly a "landmark" car, secondly a relatively rare car, and thirdly is the "sportiest" car. The 1959 4-door sedan is likewise a landmark car, which accounts for the price premium over the adjacent model years. However, it is not a rare car or a sporty car. It is a "family" car. These are the major reasons for up to $75,000 price differences within the same model year.
Before investing in an old car either through purchase or restoration, research the model thoroughly. Do not make the mistake of buying or restoring an old car just for the sake of having an old car when you can have both an old car and good investment.
Remember these broad guidelines:
If it is unusual or radical in design it may more likely be a landmark car.
If the top comes off it is usually the most valuable.
If it has 2 doors it is better than with 4 doors.
The bigger the engine (high performance) the more valuable it may be.
If it has 4 doors and needs restoration, it may cost more to restore than it will be worth.
Do your homework and be a wise and satisfied classic car investor.