For an build that I did for a customer a few years ago that wanted Vintage Air, Radio,defroster ducts, etc---but still keeping the classic 32 dash look(gauges,etc) I cut the flange (fiberglass dash) off where it mates to windshield area and added 4 inches which gave some depth to the space from firewall to dash panel for the ac unit (was a little tight between one guage and the a/c)---
I will try to find some pics of it showing work however it is the 32 that is in my gallery on this site--------