I recently bought a 1975 Thunderbird from a gentleman in Canada. This car is beautiful! It is in showroom condition. I got the car for a very good price because of an engine problem. The man told me that a couple of years ago the car overheated and he had to continue to driving it for some distance. Since then he has only started it a couple of times. The car starts pretty good put idles very rough. It is almost impossible to drive this way. I feels like a bad vacuum leak but I can't find one. I thought it may have a blown head gasket but nothing leaks on it. Does anyone have any suggestions?

Do the routine checks. Compression test, cylinder leak down, etc. I suspect you will find some internal damage has occured.

Thank you for the reply. I will check these as soon as I can.