does anyone knows a website where I can buy a classic car?

USE the GRANDDADDY of ALL classic car publications:

http://www.hemmings.com/

Ford never made a Falcon GT for the US market. Are you perhaps in Australia? If so, you may wish to look on the "local" version of eBay.

I would try going to your local bookstore and finding their magazines that are directed towards classic cars. there are always ads in the back people buying and selling. if you're willing to put forth the money and want to actually show your car when you get it, check out the aaca, they publish a member's only magazine every month that always has cars for sell and restoration companies. also try going to a few shows, you never know what you will find there, esp if you are anywhere near Pennsylvania. Carlisle has specific shows each year and they all have a car corral. good luck

did you try classiccartrader.com? heck even e-bay on a good day. google that car with for sale after it and see what comes up.

hemmings.com