a car that old, you'll have to have it checked out the old fashioned way: have a knowledgeable mechanic you trust look it over & let you know what type of condition it is in.
someone who knows what they are doing will be able to tell you if the vehicle has been in an accident by noting whether or not it has it's original paint or if any of the body has been replaced or repaired. They will be able to tell whether or not it's been flooded. they'll be able to tell you what type of repairs need to be done to the transmission & engine.
unless it's already been restored or kept in a garage the entire time, a 40 year old car will most likely be a restoration project for you.
OT about CarFax: don't be lulled into a false sense of security w/ CarFax. Every car on CarFax has at least 2 files (this will be the file that notes it leaving the factory & going to its first place of sale & at least one recall notice). Also, if the car suffers damage that the owner doesn't report to any insurance company for repairs then CarFax won't know about that damage & repair. So you still need to do your due diligence when you are buying a car even when there is a CarFax file on them.
Even if this was available most of the data would be completely useless.
Lets say for example that this report said that the car was involved in a minor accident back in 1974. If it was professionally repaired and there was no problems related to this accident after 37 years, what difference would this make.
Also, read the disclaimer on these reports. They do not guarantee any of these reports are complete or accurate. They are only as good as the data reported to them.
For example. I just got rid of a 1995 Pontiac Grand AM. I bought this car new. After the warranty was up I did all of the work myself in my own garage. I have even did some major engine repairs. It had been involved in a minot fender bender that I repaired myself. None of these were ever reported. If you were to run a Car Fax report on this car all it would show was that it was a 1 owner car that never had any major repairs or accidents. About the only thing factual on the report would be that it was a 1 owner car. The rest of the report would be completely useless.
With a car like this originality and condition means more than anything. Collector cars like this are worth the most money if they are as close as possible to the configuration as when they left the factory. I.E. the original engine, transmission, original options. For example a documented original 1971 Mustang GT is worth more than a base model Mustang. However it is common for someone to clone a base model into a more desirable GT model and try to pass it off as original. This fake clone would be worth far less money than an original GT even though they look the same. It takes lots of research to not get ripped off. There is lots of information encoded into the VIN and body tags, engine block, and cylinder heads that can help. There is also lots if places on the Internet to decode this information to see if the car is correct. If someone is trying to pass this car off as anything more than a base model make them prove it with verifiable documentation.