I am trying to reassemble my interior and specifically all the parts on the firewall before putting the dash assembly back up into place. On the right side of the firewall is the fresh air vent box that mounts above and to the right of the heater/ac box. There are 4 fasteners used to hold it in the firewall. Does anybody know whether it uses screws or bolts and in either case what size? It is hard to see but looks like the press nuts in the firewall may be coarse thread. It's been way too long since I disassembled it so I don't remember where they got put even though I bagged and tagged everything on disassembly. This is on my 92 Camaro

 

Boy, this is stretching my memory but I think it was a mix of screws and bolts. The bolts go in locations that have no captured nuts and you install a flange nut in the engine bay.

Sorry, I don't know length or size specs

 

Thanks for the thought but this is the box looking thing that inserts into the channel running down from underneath the wiper motor and the blower motor is mounted on the engine side firewall directly in front of it. It has a vacuum module to open the vent for outside are into the cabin. So, there are four mounting holes with corresponding press nuts in the firewall (actually the back of the channel that is part of the firewall). I will post a picture tomorrow.