Angus242164;98224 wroteNot familiar with that area of Corvettes I'm afraid. Are you aware of any crossover with earlier 700 series cars? I have a bunch of HVAC parts from mid '80's 760's but I think the equivalent bellows has a metal case on cars of that era.
I went through VADIS and looked at the part numbers and early pre-ECC assemblies as fitted to the 83 -85 760T. For those unfamiliar, there are a trio of vacuum assemblies on the side of the heater box - in the ECC version as fitted to the 940, this is one twin port unit, and 2 single port units.
However, the old ACC system with the thumbwheel used a single-port vacuum unit on the heater box extension, in the place where the later manual aircon systems and ECC systems use a twin-port vacuum unit. By doing a lot of Googling and cross-checking of part numbers, it would appear that the metal-cased bellows were replaced by plastic-bodied units of either Delco Remy or ACTS Ltd manufacture. The metal units (presumably on the early 760s) appear to have been superseded by the plastic units.
After all that web searching, now I can answer my own question. :)
The
single-port vacuum bellows in Seven and Nines can be replaced by Delco Remy part number
15-71503. This can replace Volvo OE part numbers 9463044, 3522973, etc which are now all unobtanium.
The
twin-port vacuum bellows is also known as Delco Remy part number
15-71438. This will replace OE part number 1388206 and a number of other numerals, which Mother Volvo had once assigned to these things before making the whole bleedin' lot disappear.
So I've ordered one of each, and when fitted, I won't have to put up with it any more ... if I'm lucky. ;)
BTW, the "gas & go" which seems to have been done with the 940 was unprofessional, but certainly not quick! It took them two days to fit the compressor and gas it up, which didn't impress me when I had to take it back
again when it wasn't working to expectations. After they lied to me about the car "being in the shop all day" in a late afternoon phone call made around the same time as my wife incidentally drove past their shop and saw the car where we'd left it that morning. I will not take it back there. Especially after it was 4 days off the road in a week and it still wasn't right.
Not sure if the requirement for dye in a/c gas is a legal requirement in NSW, but it couldn't hurt if so.