Well, I only rebutted him about the ends. What's in the middle is the trick and he's absolutely right - just finding one with the right ends does you no good if the shape between doesn't fit. Otherwise you could most likely just go down to your local Advance Auto and find one with the correct end dimensions.
I do understand that Alfa's legendary attention to precision in documentation - especially during transition years - likely precludes the right part number being paired with an inaccurate drawing
, but it may be worth considering.
But look, do you want to pin down a part number that someone has already told you is NLA or do you want to find a replacement hose for your car? If the former, then by all means keep analyzing parts diagrams. If the latter, you have been given two possible leads in this thread. Neither is a sure thing - both might be long shots - but a lot more likely to get you the part you need than pouring over old suspect diagrams.
First - my suggestions. My old note says that the correct hose was mislabeled as "non-A/C" and likely came from Vick. Vick lists exactly that part which is an awfully weird part if you think about it. Hardly any non-A/C spiders were sold in 1990 in the US. Which is why they still have the part I suppose: nobody needs it. But what if it's just mislabeled in their bin and nobody has figured it out? It's not like these outfits have '90 Spiders laying around to check for fit, what's in the database has to be assumed to be true until proven otherwise.
Second, divotandtralee has a stash of unidentified Alfa radiator hoses that he's willing to search through and if he finds a match sell you for cheap. You should consider taking him up on that kind offer.
In both cases your course of action is clear if you actually want to find a replacement hose: remove your old hose and photograph it from a few angles send them to Vick, send them to divotandtralee, send them to Classic Alfa and see if anyone has something that looks like a match. A hose listed as 1990 that looks even vaguely like yours has a high likelihood of working.