Allan - have you had any calls.
Having a 78 with CCOT type AC, same on 87 & 90. I thought yours would he the same.
But appears the 76 - 77 had VIR Type AC. Which everyone seems to deem troublesome and they get rid of it.
Ecklers, ZIP, CC all have kits to replace the Evap etc etc to convert from VIR to CCOT.
Looking at the U tubes, it looks pretty straight forward. I think pulling it down would he relatively easy and quick.
But if they offer a conversion kit, and not many OEM do VIR any more - it may he prudent to convert to CCOT.
(Cycling Clutch Orifice Tube). Any way just my thoughts. (VIR = Valve In Reciever).
Oh! I nearly forgot - yours has the issue with the steering column taking a short cut. Umm my 78 also has this issue.