very cool, i am going to check out your resto thread. i have another situation ,i was getting ready to install the ac heater box and found this little rubber (plug/vent?) in the box and cant figure out where it goes. there is an extra hole on the firewall next to the lower box drain holes but there are no screw holes in the firewall. i am pretty sure one side of the vacuum line goes to the box, but not sure where the other side goes to. i am going to post a pic.