1965 273 carb?
I pulled the original intake manifold and the original Carter 2 bbl carb off of my '65 Cuda, and they're currently sitting on a shelf in my basement.
I replaced them with a vintage Edelbrock DB3 aluminum intake manifold and a new Edelbrock 4 bbl 650 cfm carb. In my case, I did have to make some linkage modifications.
I have never really thought about selling the old Carter 2 bbl, but if you can't find one anywhere else......
Anyway, the info that the other guys are giving you (pertaining to the intake bolt hole angle) is right on. You can't put an intake manifild for a '66 or newer on '64-'65 unless you "hog" out the bolt holes. For some reason, Chrysler changed the bolt hole angle - not the pattern - in '66............ But it sounds like you're only looking for a carb, so the manifold bolt pattern should be a non-issue.