You won t be worried about what it s worth month to month because the car is worth more to you than the money it represents. Do your homework. As with most things that are collectible, not every car is as represented. Only about 500 Shelby GT 350 Mustangs were built in 1965, compared to hundreds of thousands of plain 1965 Mustang fastbacks. There are research books available on most classic cars that will tell you what to look for in the way of serial numbers and equipment to help spot the fakes.
Originality is what to look for.
Don t buy a car that has been modified from the way it originally left the factory. Buy the nicest car you can afford. This is another way of saying don t buy a car that needs a lot of work. Unless you re a master mechanic with a lot of time on your hands, buying a shabby car and paying to make it a gem will cost far more than it would have to simply wait for a perfect car to come along. Beware of auction fever.