That type of carb came on 65 Corvettes, but the one you have probably
didn't.
Corvette nuts pay high dollar for "numbers correct" parts, but to be the
correct
Holley 2818 it would have to have the model number "R2818A" and part
number "3849804" stamped on the air horn, along with the appropriate
3-digit Julian date code for their car's birthday, otherwise it's just
another Holley
aftermarket carb (that could be useful as a functional replacement).

eBay is your best bet, but don't misrepresent it as a Corvette carb unless
it has those numbers.

----------------
I must have picked up 1000 Carbs at Carlisle this summer looking for a
specific Carb for a very correct High Horse 68, that is owned by a
friend in Florida...  

My instructions were to BUY  any correct one for under $100 even if it
looked like it spent the last 30 years under water... rebuilt or
restored ones were quoted" in the $400 to $700 range.. ...and those
prices were "qoutes" from vendors IF they could come up with one...

I did not see a single correct Carb during the 3 days I looked... Its
rare when you can not find something at Carlisle..its usually just a
question of how much are you willing to pay...

Follow the advice that Wayne gave you  and see what you really have...
some are very rare some are quite common and 99 percent of us can not
tell a  correct one from one that is not correct unless we had a NCRS
book in out hands...

Bob G.    
64 72 & 98 Convertibles
76 & 79 Coupes