On the '65-'66 383 2bbl, the general location is on the rh side, about centered vertically, on the top section of the air cleaner body. As you look at the air cleaner from the radiator area, it should be about at "8:45-9:00 o'clock position). The application, by observation, was not "precise". More of a "it's on there" than in a precise piece of air cleaner body real estate.
That same general orientation was used until about '71 or so, with the later style air cleaners. The '65-'67, maybe '68 too, air cleaners were the "base plate" style, where when you removed to top to change the air filter, the whole top and sides came off as one piece, leaving the air cleaner baseplate, which the filter sat on. In about '69, they went to the later style which was "inverted" from the earlier style. When you changed the air filter element, you took off the top plate, leaving the air cleaner body on the carb.
Pictured is the engine compartment from a '70 Road Runner that was in a Hemmings article. It's the correct crinkle-finish air cleaner, but the decal placement is pretty much where they were from '71 on back to '65, and on the '65-'66 383 2bbl air cleaners. That air cleaner is the later style mentioned. It might be a tad rearward for what the single snorkel air cleaner placement was, due to the extra rh snorkle's placement. No matter if it's a B-body or C-body, they were in the same place.
CBODY67