Thanks everyone for the input. Much appreciated, and I have a nice list for next Saturday.

Starting with timing, then carburetor adjustment (as found on JamieKop's website). I've been hesitant to adjust the carburetor, as the previous owner is the long-time mechanic of the car (since the late 1970's) and is much more competent than I. Fundamentally the carburetors seem to work correctly: choke plates close upon cold startup, and gradually open as the car warms up. Cold and hot idle are set correctly. The vacuum actuated throttle control functions. (15" of vacuum at warm idle.) However, it's that "last mile" that probably makes all the difference - they are not perfectly in synch, for example.

The spark plugs are new (replaced when I bought the car) - however I'm not sure what type, and will confirm. (Compression is decent / uniform across all cylinders.)

Thanks again!!!