Does anyone know the difference between a big block heater core with air, as apposed to one without. I am converting my heater box to a big block heater core and was wondering if I could use either one? My car was originally a small block without air. thanx. wnk.

There is no such thing as a big block A/C heater core. Camaros with A/C only have a single heater core engine size does not matter.

You can't use a non A/C big block heater core the tubes are in different locations (further apart, and closer to the fender) in an A/C setup and vis versa.