As long as you have a good functional carb, don't worry too much. I was extremely lucky to find one for my restoration & it took me awhile to find it as well.
That is what I was willing to pay when I needed one.
If I get it, I get it.
I'll throw it on Ebay and see what I get. If it goes for less, I can live with it.
Besides..
I looked at it like this...
When I bought my HO, everything was correct except for the carb. One was on there, but the correct carb was sent out and nobody knew where it was.
Is it worth $2000? Depends how long someone has been looking. I have seen the 273 and 277 carbs go for $3500-4700. 271 carb not as rare, agreed, but if you are going to restore an HO and missing it...
Do I agree with a $795 AC Delco NOS air cleaner filter? $1200 weatherstrips? $700 PMD center caps? $450 for black center lugnuts? Depends. Any one of these items can make or break a correct resto and/or sale and could potentially raise the value and sale of a low production car..or at least break even on the expense.
Off my soapbox.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.