Eddie: The fit depends on the manufacturer. I have had problems with mixing-and-matching. My problems were trying to fit flanges on bases, especially finding a flange that would stay on a real flat-bottomed base. They are not always compatible.
An excellent source is McHenry Classic Car Parts. You will be speaking to Ron Normann...a very knowledgeable Camaro/Chevelle guy. I am sure he will be able to help you. Give him a call at (815) 648-1700. Sorry, no Monday morning discounts!