Last topic for now. I began work to fit air conditioning ducts into the dash of the Firebrid. The original Firebird did not have a/c. (Few convertibles in the 1960's did.) Some time ago I purchased the ducting out of a scrapped Firebird coupe that had factory installed a/c. They aren't mint condition parts, but they will do for now.
The dash of the Firebrid did not have the openings for the ducts. I completed the modification for the center duct easily since they were rectangular cuts.
The side ducts are going to be a little tougher, since they have curved surfaces intersecting curved surfaces. I again made paper templates for the holes, and checked factory photos for the proper mounting locations. The curb side vent should be straight forward enough, but I can see that I will need to make some adjustments on the driver's side to eliminate some interference between the duct and the Prius v gauge cluster. Most likely the gauge cluster will need to move higher since there is no room to move the duct parts.
Bill the Engineer