When adapting ANY donor carburetor to anything it is wise to ALWAYS (and you know how I detest that word!) use the gasket for the carburetor under the carburetor.
It is sometimes necessary to use a second gasket to seal the intake manifold.
The correct Carter YF gasket has slots that will allow intake manifold vacuum to the passages that need vacuum. SOME of the YF's have an access hole cut in the throttle body that goes nowhere. So check the passages, but use the Carter gasket, not the Rochester.
Jon
