I have an old 302 that was supposed to have come out of an old cougar 1970 is there a way to referance this through casting numbers and where would i find that info

 

I use to have a book on small block Chevy motors. It had all the casting numbers/info. This was about 1980. I see they sell books like that still. Maybe library? Before the internet. I used to buy books.
Finding if the engine you have is from a Cougar might be in one of those books.

Here are some links. I don't know if it will give the answer you seek. You might need to find somebody on a Cougar/Mustang forum. Good luck

small block ford 1970 block & head part numbers - Search