^ I think he's asking for a photo of the actual firewall view (without the box attached) from the engine side of the car... I suspect he has a shell and wants to be shown or told that the firewall opening for A/C is different between small and big block cars; the link Kurt posted above to CRG shows what it looks like but doesn't explicitly differentiate between BB & SB - I suspect, the stamped opening in the shell is common between the two, but will hope for some corroboration here... Cheers all.

The firewall cutout is the same for all cars with ac, including 6 cylinder engines.

Yes, the firewall cutout is the same but the suitcase inner is different for BB for valve cover clearance.

I updated the page - L6, SB, and BB are the same AC holes.

BB Camaro AC Suitcase
 

I lied... Apologies.
The BB Camaro AC Suitcase outer half is also different. The angle off the firewall is different between SB & BB. I did not notice until I had the two pieces side by side.

Small block inner half in foreground, angled a little more towards the engine, BB inner half behind it.

Attachment 271581