You will need to search the web for the specific parts of your car. Enter the make of your car, along with model no. and any other relevant details to check whether the parts are readily available in the market. Rustrepair.com could be your source to find the thread you are looking for. With some luck, you will be able to find people with similar hobbies.
Determine the price. As the cost involved will be high, it is essential to compare the pricing. However, in most scenarios the safe best will be to look for retro-fit auto body parts rather the buying the original, yet old parts. If you know the person whom you are dealing with, who is more than willing to give you the parts for your vintage car, then your job becomes a lot easier in terms of restoring the vehicle back to its original state.
In some scenarios, the manufactures use the same model for a number of years. With the outlook being the same, they simply offer new extension. Check whether your car belong to this category. Get hold of the Vintage Chilton Interchange Manual, also known as Mechanic’s Bible, to figure out about the history of your vehicle and the duration the specific parts remained unchanged. This will help you gauge the market of the vintage vehicle.