What type of gasoline goes in a 1966 Cadillac?

The recommended gasoline for a 1966 Cadillac is regular unleaded gasoline with an octane rating of at least 87. Some 1966 Cadillac models may require premium unleaded gasoline with an octane rating of 91 or higher. It's important to refer to the owner's manual of the specific 1966 Cadillac model in question to determine the exact gasoline requirements.