12 mpg means something is wrong, and it has nothing to do with what brand carburetor.
would be enough CFM for the 292?
There's no such thing as "enough CFM". Most engines will run with 1/2 the "calculated" CFM - they just run out of steam sooner. There was an interesting thread the other day at Mopars about losing only 1/2 seconds by running a 440 with only the primaries.
