Hi guys. I'm working on a 1980 Z28 that is a project car my friend and I own, and we got it partially disassembled. It has been a bit bastardized. Among the issues is putting together the heat and defrost assembly. This car was originally an AC car, but someone took the AC out and installed factory heat and defrost, at least partially. Among the things I can't figure out is if I have an incorrect heater assembly or an incorrect defroster duct/vent assembly. You'll see in the pictures that the defroster duct actually sits right in front of where it should connect to the heater box, and actually interferes with the movement of the blend-door (if that's what you call it). Do any of you have any ideas? Thanks in advance. I have been lurking and learning from you all for quite some time, I appreciate all of your knowledge.