measuring the offset of the wheel and the car inner fender width should tell you. the actual cragar wheel should have a slight slot in the stud hole for a step style lug nut, this allowed 4.5 and 4.75 patterns

I believe factory specs on the bel air was 7.5x14 You can always contact Cragar and I'm sure they would be able to help. 1-800-345-4545