Any Carter BBD made for a 1970 or newer vehicle will have the correct fitting for the thermostatic air cleaner. Take a look at the photo below; I've drawn a red arrow to the correct vacuum nipple for the thermostatic air cleaner hose:
If you don't get vacuum at this fitting, then you've probably got the wrong carburetor base gasket and you'll have other running problems as well. The hose that connects to this fitting runs to one nipple on the thermo sensor (round flying-saucer looking thing in the bottom of the air cleaner base; the hose nipples protrude downward through the floor of the cleaner base). Another hose then runs from the other thermo sensor nipple to the vacuum flap actuator.
I'll have to look at the base plate and see why I am not getting any vacuum , I think I saved the origonal to compare. Can I run it this way for a little while and not hurt anything? Thanks Steve