Figure out who can run a scan of the national database for you and see if it is still actively titled or register somewhere. This can be done through local law enforcement usually. That's the best way to get started.
1968 400 Coupe, verdoro green, black vinyl top 1968 400 Convertible, verdoro green, black top 1971 Trans Am, cameo white, auto 1970 Buick Skylark Custom Convertible 350-4(driver)